COBB Hatchery Management Guide

The measure of success of any hatchery is the number of first-quality chicks produced. This number expressed as a percentage of all eggs set for incubation is normally termed hatchability. Hatchability is influenced by many factors. Some of these are the responsibility of the breeding farm and others are the responsibility of the hatchery. Mating activity is a good example of a factor entirely influenced on the farm. The hatchery cannot alter it, although many other factors can be influenced by both the farm and the hatchery. Controlling factors Farm Hatchery Breeder Nutrition Sanitation Disease Egg Storage Mating Activity Egg Damage Egg Damage Incubation - management Correct Male and Female BW of setters and hatchers. Egg Sanitation Chick Handling Egg storage Thus, the breeder farm has a major influence on results at the hatchery and it is essential for the farm and hatchery to work closely together. COBB Hatchery Management Guide COBB 2. Hatch of fertile Because hatcheries have no influence over fertility, it is important to consider hatch of fertile in addition to hatchability. The hatch of fertile percent is a measurement of the efficiency of the hatchery machinery. Hatch of fertile takes into account the flock fertility as well as hatchability; it is percent hatch divided by percent fertile times 100. Example: (86.4% Hatch ÷ 96% Fertile) * 100 = 90% Hatch of Fertile The following example clearly shows the value in calculating Hatch of Fertile. Even though Hatchery B has the lowest % Hatch, it has the highest % Hatch of Fertile. This is because % Hatch was limited by fertility and not by the hatcheries ability to effectively hatch eggs; therefore, Hatchery B is clearly performing the best, provided chick quality is equal. At peak production, flocks should be achieving at least 96.7% fertility and 93.5% hatch of fertile. Fertility and hatch percent standards are set according to the age of the breeders. The benefits of recording Hatch of Fertile are as follows: 1. Separates fertility and hatchery problems 2. Allows you to focus on the problem 3. Expedites troubleshooting Hatchery % Hatch % Fertile % Hatch of Fertile A B C 86 82 84 97 91 94 88.66 90.11 89.36 Breeder age Hatch of fertile (weeks) (%) 25 to 33 >90.2 34 to 50 >91.8 51 to 68 >88.6 2 COBB Hatchery Management Guide COBB 3 3. Hatching egg management Optimum hatchability and chick quality can only be achieved when the egg is held under optimum conditions between laying and setting in the incubator. Remember that a fertile egg contains many living cells. Once the egg is laid, its hatching potential can at best be maintained, not improved. If mishandled, hatching potential will quickly deteriorate. Use of floor eggs depresses hatchability. They should be collected and packed separately from nest eggs, and clearly identified. If they are to be incubated, they should be treated separately. Prevent hair-line cracks by handling eggs carefully at all times. Place hatching eggs carefully into the setter tray or transport tray, small (pointed) end downward. Take care with egg grading. During the early production period check the weight of borderlined sized eggs to select hatching eggs. Store the eggs in a separate room in which the temperature and humidity are controlled. Keep the farm egg handling room clean and tidy. Maintain good vermin control in your egg room. Refuse to accept dirty egg containers and buggies from the hatchery, and take care of them while on your premises. Good egg 1. 2. 4. 5. 6. 7. COBB Hatchery Management Guide 4 COBB Remove and discard eggs unsuitable for hatching. These are: • Dirty • Cracked • Small (According to Hatchery Policy) • Very large or double yolk • Poor shells - but any shell color should be acceptable for hatching • Grossly mis-shapen Blood stained Elongated Wrinkled Cracked Rounded Dirty Toe punched Small and double COBB Hatchery Management Guide COBB Eggs should be collected from the farms and transported to the hatchery at least twice a week. There are three storage areas: farm egg room, transport, and hatchery egg room. It is important to match the conditions in each of these situations as closely as possible to avoid sharp changes in temperature and humidity, which can lead to condensation (“sweating”) on eggs or eggs being chilled or overheated. Also, temperature fluctuations must be avioded during transport and storage. The temperature decrease must be a smooth transition when cooling the eggs from the hen house to the hatchery egg room, and also a smooth transition when warming the eggs from the hatchery egg room to the setter machine. 5 3.1 Key points on egg storage Egg Temperature Flow Chart (for fresh eggs) Hen House 75 - 85º F 24 - 29º C On Farm Egg Room* (see note below) 70 - 77º F 21 - 25º C Preheating Area 75 - 80º F 24 - 27º C Egg Transportation Truck 68 - 73º F 20 - 23º C Setter Machine 99.5 - 100º F 37.5 - 37.8º C Hen’s Body 104 - 106º F 40 - 41º C Hatchery Egg Room (see item 3.2 for details) 66 - 70º F 19 - 21º C NOTE: *Lower temperature for eggs stored at the farm. Higher temperature for eggs transported to the hatchery daily. COBB Hatchery Management Guide 3.2 Optimum Egg Storage Conditions A relationship exists between the length of time eggs are stored and the optimum temperature and humidity for best hatchability. Generally, the longer eggs are to be stored, the lower the storage temperature and vice versa. 69 68 67 66 65 64 63 62 61 60 59 0 3 6 9 12 15 18 Days of storage 20 19 18 17 16 15 21 °f °c Optimum temperature range for egg storage 6 COBB COBB Hatchery Management Guide COBB 7 The main effects of storing eggs are: Storage prolongs incubation time. On average, one day’s storage adds one hour to incubation time. This must be taken into account when eggs are set, so fresh and stored eggs should be set at different times. Hatchability is depressed by prolonged storage. The effect increases with storage time after the initial six-day period, resulting in losses of 0.5 to 1.5% per day with the percent increasing as storage extends further. Chick quality will be affected and hence broiler weights can be depressed in chicks from eggs that have been stored for 14 days or more. 1. 2. 3. 3.3 Effects of Egg Storage Gas exchange can occur through the pores in the egg shell during storage. Carbon dioxide diffuses out of the egg, and its concentration declines rapidly during the first 12 hours after the egg is laid. Eggs also lose water vapor while in storage. This loss of both carbon dioxide and water contributes to the loss in hatchability and chick quality after storage. Storage conditions must therefore be designed to minimize these losses. Most eggs are placed in open-sided cases or farm racks, but some are placed in solid covered cases. Allow covered eggs to cool down and dry thoroughly before casing to avoid condensation and subsequent mold growth. To avoid temperature shock to the embryo and consequent condensation on the shell, eggs should be removed from the egg room and pre-warmed before setting. Ideally, eggs should be pre-warmed in a purpose-built room at around 75-80 °F (24-27 °C) so that all can achieve the desired temperature. Effective air circulation and correct room temperature are essential to achieve the necessary even pre-warming of eggs. Uneven pre-warming increases variation in hatch time - precisely the opposite of the desired effect of pre-warming. Even with good air circulation, it will take 8 hours for eggs on a buggy to reach 78 °F (25 °C), irrespective of their initial temperature. With poor air circulation, it may take twice as long. So the recommendation is to: • Provide good air circulation around the eggs. • Allow 6 to 12 hours for pre-warming. 3.4 setting eggs 3.5 setting time Three factors influence the total incubation time of eggs: Temperature of incubation: normally fixed for any hatchery, but to achieve a desired pull time for chicks, variation in the time at which eggs are set can be modified according to age and size of eggs. Age of the eggs: stored eggs take longer to incubate. You will need to add extra incubation time if eggs are stored over 6 days. (1hour per day of storage) Size of the eggs: larger eggs take longer to incubate. 1. 2. 3. COBB Hatchery Management Guide 8 COBB 4. Setter Operation Energy consumption, labor usage, durability, maintenance and capital costs influence the design of incubators. The optimum physical conditions for any broiler embryo to grow successfully are: • Correct temperature • Correct humidity • Adequate gas exchange • Regular turning of eggs Commercial incubation systems fall into three main categories: • Multi-stage fixed rack • Multi-stage buggy loading • Single-stage buggy loading The actual quantity of eggs to be loaded in each machine at each set, the frequency of loading (once or twice a week) and the actual position of the set within the machine will vary with each manufacturer. Operate the machine according to the rules laid out by the manufacturer. Do not abuse them. Setters normally draw fresh air from the room in which they are situated. This fresh air supplies oxygen and moisture to maintain the correct Relative Humidity. Air leaving the setter removes carbon dioxide and excess heat produced by the eggs. The air supply to the setter room should be 8cfm (13.52 cubic meters hr) per 1000 eggs. See chart on page 8 (Hatchery Ventilation - Correct set-up). All setters have a humidity source that can control various levels of relative humidity. The fresh air supplies relatively little moisture, and so to reduce the load on the internal humidification system, air entering the machines is pre-humidified to closely match the internal relative humidity. The temperature of this air should be 76-80 °F (24-27 °C). Multi-stage setters require a constant amount of air. It should be adjusted so that the carbon dioxide level within the machine does not exceed 0.4%. Most fixed rack machines run at 0.2-0.3% and buggy machines 0.3-0.4% but these elevated CO2 levels are not required. 1. 2. 3. 4. 4.1 VEntilation COBB Hatchery Management Guide COBB 9 Egg Receiving Holding Area Setter Room Hatcher Room Chick Holding Rooms Chick Take-off Wash Room Clean Equipment Room Hallways 66-70 66-70 76-80 76-80 72-75 72-75 72-75 72-75 75 19-21 19-21 24-27 24-27 22-24 22-24 22-24 22-24 24 60-65 60-65 55-62 55-62 65-70 65-70 65-70 N/A N/A Neutral to +0.01 Neutral to +0.01 +0.015 +0.02 +0.005 to +0.01 Neutral -.015 to -.025 -.015 to -.025 Positive Neutral 2 8 17 40 3.38 13.5 28.7 67.6 (5 minute air exchange to room) (0.5 minute air exchange to room) (0.5 minute air exchange to room) (1 minute air exchange to room) (5 minute air exchange to room) Ventilation Rate Temperature Relative Humidity Area Pressure in relation to atmosphere: (cfm /1000) (m3/hr Areas /1000) °F °C (%) (in H2O) Hatchery ventilation - the correct set-up to 21.6 17.28 12.96 8.64 4.32 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 250 200 150 100 50 0 kjoules/egg/day Watts/1000 eggs age (days) Heat production of incubating eggs Pressure Conversion (0.01 in H20 = 2.5 Pascal’s, 0.01 mbar, 0.1016 mm H20) Relationship between average hatch time, hatchability and temperature 100 90 80 70 60 50 40 30 20 10 0 35 36 37 38 39 40 Hatchability % average hatch time (days) temperature °C 24 23 22 21 20 19 °F 95 96 97 98 99 100 101 102 103 104 105 4.2 Temperature Control Temperature determines the metabolic rate of the embryo and hence its rate of development. In a multi-stage machine, temperature should remain constant. The optimum temperature for both hatchability and chick quality will differ depending on the type of incubator. Higher or lower temperatures than the manufacturer’s recommendations will lead to faster or slower development and consequent reduction in hatchability. In single-stage incubation, temperature can be altered for the growth of the embryo and increased animal heat production, starting at a higher temperature and reducing in stages through transfer. Incorrect balance in loading multi-stage setters can create major temperature variations. Partly filled machines may not achieve the correct temperature and prolong incubation, while loading double sets can create overheating problems. Both conditions will adversely affect hatchability and chick quality. 4.3 HUMIDITY During incubation, water vapor is lost from the egg through the pores of the shell. The rate at which this moisture is lost depends on the number and size of the pores (the gas conductance of the shell) and the humidity in the air around the egg. For best hatchability, an egg must lose 12% of its weight by 18 days of incubation. Due to differences in shell structure and hence gas conductance, when all eggs are incubated under the same humidity conditions, there will be a variation in moisture loss. With eggs from broiler breeders, this variation does not normally have any significant effect on the hatchability. However, when age, nutrition or disease reduces the eggs’ quality, it may be necessary to adjust incubator humidity conditions to maintain optimum hatchability and chick quality. 1. 2. Optimum weight loss of eggs during incubation (multi-stage) 12 11 . 10 . 9 . 8 . 7 6 5 4 3 . 2 1 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 Days Weight loss % COBB Hatchery Management Guide 12 COBB 4.4 Turning Eggs must be turned during incubation. This prevents the embryo from sticking to shell membranes, particularly during the first week of incubation, and aids development of the embryonic membranes. As embryos develop and their heat production increases, regular turning will aid airflow and assist cooling. 5. Egg Transfer Eggs are removed from the setter after 18 or 19 days and transferred to the hatcher trays. This is done for two reasons. The eggs are laid on their sides to allow free movement of the chick out of the shell at hatching. It also assists hygiene; large quantities of fluff are generated during hatching and could spread this potential contamination around the hatchery. Transferring too early or too late will result in embryos being subjected to sub-optimal conditions causing lower hatchability. This should be considered in any decision to vary the transfer time. Transfer times will differ according to the different types of setters (18 to 19 days are usually the norm). The transfer operation should proceed smoothly and quickly to avoid cooling the eggs as this will delay hatching. At transfer, eggs may be candled to enable clears (infertiles and early dead germs together with rots) to be removed and counted. Shells are more brittle at this stage because the embryos have withdrawn some of the shell calcium for skeletal development. Therefore, care must be taken when transferring eggs to avoid breakages. Rough handled eggs at this stage may cause ruptures and hemorrhages. Automated transfer equipment enables this task to be carried out more gently than a manual system. Ensure the hatcher trays are properly washed and allowed to dry before eggs are transferred. Eggs in wet trays will cool down while the water is evaporating in the hatcher. Hatchers must be dry and up to proper temperature proir to transfer. Dispose of ‘rots’ and ‘exploders’ in a container of disinfectant. In-ovo egg injection systems are now available, which may be considered for Mareks protection and administration of other vaccines. Manufacturers’ recommendations for use must be followed. 6. Factors Influencing Chick Size Egg size is the main factor affecting chick size. Chick weight is normally 66-68% of egg weight. Thus, chicks from eggs averaging 60 grams will on average weigh around 40 grams. Individual chick weights are likely to range from 34 to 46 grams. Egg weight decreases because of water loss during incubation. This also contributes to chick weight variation from eggs of the same size. Length of time between hatching, pulling, and delivery also affect final chick weight. Time spent in the hatcher will have a greater effect than time at the lower temperature of the chick room or delivery vehicle. 75 70 65 0 24 48 72 % of egg weight Hatch from shell time (hours) Related Chick Weight 7. OPERATION OF HATCHERS Most broiler hatcheries hatch twice a week from each hatcher. The hatcher will be washed and disinfected between hatches, which means durability of construction and ease of cleaning are vital factors. Air supplied to the hatcher fresh air plenum should be 17cfm per 1000 eggs (28.7 Cubic meters per hr). From point of transfer to pipping, airflow and humidity in the hatcher should be maintained the same as in the setter. Moisture is important during the hatching process to ensure the shell membranes remain soft and pliable so that the chick can escape unhindered. When pipping starts, the moisture level will rise causing the wet bulb temperature to also rise. At this point, the damper will require adjustment to maintain this level. Additional moisture may be required from the spray system. A few hours before take off the damper is opened to increase air supply for the chicks. Hatcher temperatures are usually slightly lower than those of the setter to reduce the risk of overheating. 7.1 Ventilation and Humidity 7.2 temperature 8. Chick Pull and Processing Chicks are ready to be taken off when most of them are dry and fluffed up, with a few (about 5%) still having some moisture on the backs of their necks. A common mistake is to allow chicks to spend too long in the hatchers so they dehydrate excessively. Dehydration of chicks may result from incorrect adjustment of setting time for egg age or excessive weight loss during incubation. Similarly, if they are “green”, e.g., not yet ready, check setting times and also check for opportunities for the eggs to have become cooled down in incubation, reducing the rate of development. Upon pulling chicks, they have to be separated from their debris, graded into first quality and culls, and counted into boxes. Some hatcheries carry out additional operations such as: Sexing, primarily using feather-sexing with broilers but also Vent sexing with breeding stock Vaccination, sprayed or injected, using hand or automatic vaccinators Beak conditioning During processing, chicks must be held in a controlled environment that prevents overheating or overcooling. They must not be overcrowded in the boxes or while on conveyers. To reduce weight loss from the chicks, maintain the correct humidity in the chick holding areas. Aim for 23 °C (73 °F) with a relative humidity of 65 - 70%. Automated equipment has been developed to improve chick handling while reducing the number of staff involved. Avoid rough handling of chicks in manual operations and when equipment is used. Equipment must be correctly and regularly maintained. Clean all equipment thoroughly after each hatch. All chick contact areas such as conveyers and carousel must be easily accessible for cleaning. 8.1 Feather Sexing Broiler Chicks Broiler chicks in the feather sexable - slow feather format, can be feather sexed at day old as illustrated below. In the non-feather sexable - fast feather format, both males and females will show the same pattern of feather development illustrated by the diagram below relating to females. TOP OF WING A-Primaries B-Coverts At hatching all feathers short but coverts extend only 1⁄2 to 3⁄4 length of primaries After several hours feathers longer but coverts still 1⁄2 to 3⁄4 length of primaries 1. Spread wing out like a fan. 2. Look at feathers on outer joint - bottom row of feathers are primaries, top row of feathers are coverts. 3. When the bottom row (primaries) of feathers is longer than the top row (coverts), the chick is female. 4. When the bottom row (primaries) of feathers is the same length, or shorter than the top row (coverts), the chick is male. Coverts and primaries extend same length Coverts extend slightly beyond primaries Coverts extend greatly beyond primaries FEMALES Coverts always shorter than primaries MALES Coverts always as long as or longer than primaries 8.2 THE HATCH WINDOW The hatch window indicates the number chicks hatched after the eggs have been transferred from the setter to the hatcher. If the eggs are hatching too early, the chicks become susceptible to problems such as dehydration. Dehydration of chicks this early could lead to increased 7 and 14 day mortality and poor broiler performance. If the chicks are hatching too late the result could be poor hatchability, chick quality problems, increased pipped eggs and live embryo unhatched eggs. Factors affecting early hatch include: Factors affecting late or delayed hatching include: Extended pre-heating periods Setting eggs too early. Too many hours of incubation Incorrect setter/hatcher temperature and humidity Hot spots inside the setter and hatcher Incorrect ventilation Seasonal temperature changes effecting the hatchery environment Too many fertile eggs in the hatcher Egg size Setting eggs too late Incorrect setter/hatcher temperature and humidity Incorrect ventilation Seasonal temperature changes effecting the hatchery environment Eggs which have been stored for long periods Eggs which have stored at too low a temperature Incorrect setting patterns in multi-stages machines Disease and fertility problems COBB Hatchery Management Guide 18 COBB Ideal % Hatched Hour 100% = -43 80% = -38 60% = -33 40% = -23 20% = -13 0% = 0 top Middle Bottom The bar graph above indicates eggs which were in the top, middle and bottom positions in the setter and then transferred to the hatcher. Ideally, no more than 25% of the total hatch should be hatched 23 hours before pull and more than 75% of the total hatch should be hatched 13 hours before pull. This bar graph indicates the correct number of chicks hatching spread over the 23 hours prior to pull. The number of chicks hatched in each hatcher basket / tray should be even throughout the hatcher. Ideal Hatch Spread Hour 70-60-50-40-30-20-10-0 -43 -38 -33 -23 -13 0 top Middle Bottom 9. Hatchery Waste Disposal With an average of 85% hatchability, 15% of the eggs will be either infertile or contain dead embryos. These eggs, together with the eggshells that remain after pulling chicks, constitute hatchery waste. Legislation in some countries now prohibits the incorporation of hatchery waste into by-product meal due to the risk of spreading pathogenic organisms. There are very few profitable outlets for this material and most hatcheries will have to dispose of this as waste. Unhatched eggs from the hatcher tray should be macerated to destroy any unhatched embryos. Pipped eggs and cull chicks should be destroyed using carbon dioxide gas or other locally acceptable procedure. Macerated debris can be augured into a bin or trailer, or removed by vacuum into a sealed storage hopper. This should be disposed of according to local practice and environment constraints. 10. Chick Transport Specially designed vehicles must be used to control the chicks’ environment throughout the journey from hatchery to growing farm. The minimum ventilation rate needed to satisfy adequate oxygen is 20 CFM (34 m3/hr) per 1000 chicks during winter weather, and twice this amount during hot weather. The vehicle should be equipped with an auxiliary heating system but may use fresh ambient air for cooling. If summer air temperatures exceed 86 °F (30 °C), cooling equipment is required. The vehicle cab should have a display showing the temperature within the load to enable the driver to adjust air vents for cooling. Chicks should be held at an in-box temperature of about 90 °F (32 °C) that can usually be achieved by a vehicle air temperature of 75 °F (24 °C) with plastic boxes or 71 °F (20 °C) with cardboard boxes. Chicks delivered in plastic boxes require greater care to prevent overheating or chilling than those in cardboard. Ensure the vehicle has adequate heating and cooling to handle plastic boxes. Boxes must be correctly stacked and spaced to allow free air movement around them. Each row of boxes should be locked with a bar running the full width of the vehicle to prevent any movement during the journey. The vehicles can be provided with a rear plastic curtain to help retain heat while chicks are being unloaded. Chick delivery drivers must be well trained and conscientious. Each driver should start the day with clean clothing and should change into fresh coveralls/footwear for each delivery. It is preferable for drivers not to enter the poultry house. Power wash delivery vehicles with detergent/disinfectant on each return to the hatchery. Vehicles should carry a disinfectant spray so that the wheels can be cleaned between farms if delivering to more than one location in a day. Chick boxes returning to the hatchery represent a high health risk. They must be kept separate and thoroughly washed and disinfected before re-use. 11. Altitude In several countries, poultry are produced at relatively high altitudes. Hatcheries operated at high altitudes experience reduced hatchability, with much greater effects above 2500 ft (762 m). Barometric pressure declines with altitude, as does partial pressure of oxygen and absolute humidity. Fresh air ventilating will tend to be colder and drier than at sea level. Incubators with poor temperature or humidity control systems will be less able to cope with these conditions. Hatchability problems at high altitudes are due to reduced availability of oxygen in the air and increased moisture loss from the eggs. The oxygen percentage of fresh air is always 21.6% and room/machine conditions must never go below 20%. The reduced partial pressure at altitude provides less oxygen from a given volume of air. This pressure reduction results in lower blood oxygen level and lower availability to the tissues. Water loss from an egg during incubation is greater at high altitudes because water vapor diffuses through the shell more rapidly. The conductance of the eggshell becomes extremely important at high altitudes. Setters will need to be adjusted to ensure that the weight loss of the egg is 12% by 18 days of incubation. 11.1 Oxygen Availabili ty 11.2 Water Loss 12. Maintenance As hatcheries become larger and more automated, the need for preventative maintenance becomes crucial. Below are some suggestions: Obtain manufacturers’ recommendations for routine servicing and maintenance. Carry out regular maintenance based on these guidelines and your own experience. Perform a thorough inspection and cleaning at least once a year on multistage setters. The turn-around time for hatchers is extremely rapid and leaves little time for servicing and repair. Have a spare machine to enable essential repairs to be carried out when necessary. Keep a stock of regularly required spare parts and maintain an accurate inventory of items purchased and used. Make sure staff who operate setters and hatchers are properly trained and familiar with their operation and have a procedure to follow in the event of machine failure. Ensure adequate safety precautions are adopted. Provide the necessary guards and safety switches. Ensure all working practices comply with safety legislation. This is a management responsibility. 12.1 Preventative Maintenance • Calibrate machines • Calibrate rooms • Check moisture loss • Check pipping • Check spread in hatch time (first chicks to final chicks) • Verify that programs are yielding intended results • Share information between management and maintenance personnel 13. Hatchery Automation Because of increasing hatchery size, and increased cost of labor, considerable opportunities may exist for automating many of the labor-intensive operations in hatcheries. As a broad guide, a staffing level of one employee per one million chicks per year (not including drivers) is the norm without automation, or one employee per two million chicks per year with automation. Machines are available to: a. Grade eggs before setting b. Candle and transfer eggs at 18 days c. Perform in-ovo vaccination d. Separate chicks from debris e. Count chicks f. Spray, vaccinate and box chicks g. Remove debris A range of conveyors, elevators and carousels are available to speed up grading, sexing and other operations which need to be manually performed. Much of this equipment is precision made and very expensive and only very large hatcheries can justify its use. Nevertheless, smaller hatcheries can achieve benefits from equipment such as vacuum transfer machines and chick-grading carousels, which are inexpensive but deliver considerable productivity benefits. Productivity improvements are realized by: a. Gentler handling of eggs to reduce breakage b. More precise vaccination of the chicks c. More accurate counting of chicks d. Less fatigue on operators and the creation of a better working environment When selecting equipment, ensure that it can be disinfected easily, quickly and effectively. Egg and chick handling equipment should not contribute to cross contamination between eggs or between chicks. COBB Hatchery Management Guide COBB 23 14. Hatchery Design Good design is essential for cost-effective hatchery operation. Hatcheries form part of the food chain and their design must therefore incorporate food hygiene standards. The conditions provided to maintain embryonic growth in the incubators are also ideal for the growth of bacteria and molds. The outer surfaces of eggs must be free from contamination and all room surfaces, items of equipment and incubators must be designed to allow simple, regular and effective cleaning and sterilization. Durable wall and floor finishes and easy-to-clean drains. Wall surfaces should have a minimum of joints and fastenings that impede effective cleaning. A good floor finish can be obtained with a cement incorporating a hard stone aggregate, or topped with a self-leveling epoxy which has certain advantages over the more traditional finishes. The floor must be sloped to drains in each room of the hatchery. All drains need to be trapped, particularly in hatching and pull areas, to prevent blockages from eggshell and debris. The entire drainage system must be designed to handle large quantities of wash water and solid matter. A biosecure flow of eggs, chicks and equipment through the building. Clean and dirty areas must be separated to prevent cross-contamination by fluff that can be carried around the hatchery on air currents, on staff clothes and on equipment. The ventilation system must ensure that air moves from the clean to the dirty areas and never the reverse, e.g., in the same direction as the eggs, from setters to hatchers. Ventilation systems themselves need to be suitable for periodic cleaning. In this context, the polythene air duct offers many advantages over steel trunking systems that are difficult to clean. 14.1 Structure Hatcheries should have the following features: Introduction With the introduction of a dependable variable speed fan and a pressure sensing and controlling device, it is now possible to successfully exhaust a hatcher or incubator into a controlled plenum. Advantages Creating a hatcher or incubator plenum offers several advantages: Modifications of hatchery construction designs can now vary from the traditional “T” shaped building, because hatchers will no longer require an exterior wall to exhaust. Controls the variable atmospheric conditions that may prevent the correct exhaust of the hatchers or incubators. Eliminates all ductwork that must be balanced, monitored, and properly adjusted for consistent machine operation. Aids in hatchery sanitation and cleanup and reduces man-hours needed for tedious duct cleaning. Reduces or eliminates chick down exhausted into the atmosphere. Installation Following is a step-by-step guide to installing the plenum with variable speed fan and pressure control:

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