Biosecurity in the hatcher and beyond; a "how to" or a "how about"!
I'm sure you know the basics of hatchery biosecurity.
· Keep it clean - it isn't because you can't see it that it isn't there
· Keep it in one direction and - go from clean to dirty areas only
· Know from where the air blows - contaminated air shouldn't flow back to cleaner areas
The same applies for the hatchers in the hatchery. These are probably the dirtiest and most concentrated areas of the hatchery.
Prior to use: Prior to using the hatcher the machine should be clean, dry and free from any contaminants. Make sure that the hatcher baskets are completely dry before the transferred and candled eggs are settled in the hatcher baskets. Although the eggshell is protected by a thin layer called the cuticle, which breathes and protects the delicate innards of the eggs, it is not resistant enough to protect the eggs when they get wet. Sweating eggs are often a sign of contamination and run the risk of becoming exploders in the hatcher.
A sensible action is to fumigate and disinfect the hatcher prior to use.
Let us look at the different sections of the hatcher and how to keep them bio-secure.
Central console, doors and walls:
· Central console: Hatchery managers often are reluctant to spray wash or disinfect the central console that houses the electronics that steer the hatcher. Nevertheless cleaning and disinfecting the console are an important part of keeping the hatcher clean. Ensure that cleaning the console is done following the suppliers strict guidelines. Ideally the console consists of a single piece mold so that all the water and disinfectant can reach any open area and easily flow out
· Walls: Have smooth walls so that dirt cannot easily grip to them. All connections should be smooth and be easily accessible. Use an effective and foaming disinfectant that adheres properly to the walls. Let the hatcher dry thoroughly. You can even use a heater dryer to accelerate the process.
· Doors: Preferably have completely sealed doors that don't leave a gap or a wrongly folded rubber flap under the door. Drop-down doors with bezel-hinges seal incubators hermetically. The doors raise up by a few centimeters when opening and goes back down when closing. (Fig 1) This is evermore important when the chicks hatch in the hatcher as a considerable amount of fluff is produced. This fluff contains the aspergillus spores and easily escape under doors that don't seal correctly. You have probably witnessed hatcher corridors full of fluff in many hatcheries. To be sure not to contaminate from the hatcher area to the transfer area doors should be kept closed. This is especially important at the time the hatcher doors are opened. When, at the end of the hatching cycle the hatcher doors are opened and there is an amount of fluff in the hatchers contaminating the corridor then the transfer area doors should remain closed until the hatcher area has been cleaned and disinfected.
Chassis and housing: Fig 2 If the hatcher has a chassis it should be a closed- type chassis whereby there are no openings where water and/or fluff can be deposited or stand still without being able to be washed out. Standing water, even disinfected water can become a source of contaminants when stagnant.
The most common area of contamination is the area above the hatcher. Incubators with direct-drive motors don't require a drive belt and motor above the machine and then have an opening through the top of the hatcher. This opening is often the source of much contamination into the hatcher. It is also a prime source of contamination form one hatcher to the other and regularly overlooked as a place to clean. Fig 3
Fig 2 Fig 3
Fluff tunnel or Plenum:
A large amount of fluff is produced during the hatching process at the time of pipping. This fluff is not free from pathogens, usually Aspergillus and often Aspergillus Niger that grows well in hot and humid environments. The fluff flies around the hatcher while the fanblades are mixing the ambient air before being expulsed through to the plenum ( the small corridor behind the hatcher) where it usually settles down on the floor. Cleaning the plenum properly is often a difficult job as the plenum connects to many hatchers that are in different stages of incubation. As one hatcher is at its "end of the hatch"-stage with all the fluff expulsed in the plenum, the next hatcher is just starting to produce fluff. Incubators that run a "Dry Hatch", which is only possible with cooling water above the dew point, are fitted with fluff bags. These bags collect the expulsed fluff leaving the plenum clean and free from fluff. There are studies today for adding an anti-microbial impregnation of the bag. The fluffbag is the first filtration that also saves a lot of money by extending the air-handling units' filters (second filtration).
Fig 4 Clean does not however mean disinfected. The plenum always needs to be disinfected after a hatch. Humid plenums form a particular concern. They show that most of the humidity from the hatcher hasn't been evacuated resulting in fluff sticking to all the plenum walls making them harder to clean .
Condensation: The main issue for bio-security is condensation. Water is the enemy of incubation. Fig5. Because we are talking about an incubator the theory is simple: "Just add water and it will grow." This means that anything alive in an incubator will grow more when water is added. Also when water evaporates it causes cold spots which can influence the hatchability and the uniformity of a batch. In traditional incubators the cooling water temperature is usually between 10 and 15°C. "Dry Hatch" incubators cool the incubator with water of 27°C. This temperature is above the dew point. The Dew point is the point at which water vapor changes into liquid water upon contact with a solid mass. The dew point can be calculated and will depend on the temperature and the relative humidity. So any water temperature above the dew point will NOT cause condensation. No condensation on the cooling tubes or any condensation dripping onto the floor effectively eliminates any mold, fungal or bacterial growth. As the hatcher is free from contamination, free from condensation it remains dry. Traditional hatchers that aren't running a "dry hatch" will, especially in hot and humid climates, overwork their cooling systems resulting in excessive condensation and wet floors which will cause eggs close to the floor to become too cold and thus affecting hatchability and uniformity.
So having condensation in the hatcher cooling tubes and on the floor not only forms a bio-security risk and increases the need for intensive disinfection but the water on the floor affects different parts of the incubation program.
A reminder that the basic elements of the incubation are, fertile eggs, Temperature, Ventilation and Humidity all working together. When condensation occurs all these are working against each other. At the time of pipping the humidity peaks. The hatcher program will open the ventilation and increase the air-flow to evacuate the excess humidity while trying to keep the temperature stable. Because there is still water on the floor and cooling tubes the hatcher doesn't dry out very fast. The humidity stays high as long as there is still water in the hatcher. Subsequently the chicks take longer to dry and become fluffy. Those chicks that haven't broken out of their shell yet aren't given enough time to dry and become second class chicks. The uniformity is therefor affected and the hatch-window increases even though a CO2 program might have been used. The speed at which the humidity drops in the hatcher directly affects the drying time of the chick and more importantly the closing of the chicks' navel. Fig 6.
Chicks that hatch in a contaminated high humidity environment run a high risk of first week mortality due to various bacteria such as Strep's or Staph's because the navel doesn't close within the first few hours.
Using CO2 steering together with a "Dry hatch" incubator significantly shortens the hatch window and possible contamination time.
Cleaning: Post hatch, when the chicks have been pulled from the hatcher, the machine is left dirty and wet. It will contain fallen eggshell, excrement and fluff. The fluff will also contain the aspergillus spores and other pathogens. The hatcher needs to be disinfected or fumigated and the baskets and trolleys need to be cleaned and dried ready for a new bio-secure hatching cycle.
Finally, beyond the hatcher, the handling of day old chicks that are still wet and have not hatched in optimal conditions run the risk of severely under performing or dying.
Post hatch, to protect the chicks, try to handle the chicks as gently as possible so as not to harm them. Keep the bio-security high going forward to the farms. At the time of hatching the chicks, as with all animals and humans, quite hypo-sensitive (insensitive to stress) to all kinds of stresses and external stimuli but are quite sensitive to many types of infection.
Daniel Abrahams firstname.lastname@example.org
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Article made possible through the contribution of Daniel Abrahams and Emka Incubators