EGG HYGIENE

FACT: AN INCUBATOR WILL HAPPILY INCUBATE PATHOGENS ALONG WITH OUR EGGS.

The warmth and humidity that favour embryo development also favour the multiplication of bacteria, fungi and other pathogens. A microbial load on the eggshell can quickly multiply, invade and kill an embryo.

The egg's natural protective coating, known as the bloom or cuticle, is its first defence against attack. Under normal conditions it is remarkably effective, which is why we avoid disturbing it by washing or scraping eggs unnecessarily.

However, there are times when we see an increase in early embryo losses, blood rings, or we know that contact-transmitted disease is present in the breeding pens. Good egg hygiene therefore begins long before the eggs are placed in the incubator.

Good hygiene begins in the breeding pen

Always collect eggs before attending to other tasks in the pens. Feed, water, mud, manure and sick birds all increase the risk of transferring contamination to the eggs.

As a matter of routine:

• Collect eggs before feeding and cleaning.
• Keep nesting areas clean and dry.
• Wash your hands before handling eggs or opening the incubator.
• Never touch eggs after handling sick birds or removing dead chicks from the brooders until you have thoroughly washed your hands.
• If eggs have been washed, handle them afterwards with clean gloves.

Remember that your hands, boots and clothing may be carrying pathogens from one area to another.

Egg cartons are part of the hatchery

Used cardboard egg cartons can be sanitised in a pre-warmed oven at 70°C for 10 minutes before being reused for egg storage.

If your oven does not go down to 70°C, simply use its lowest setting. Cardboard egg cartons are themselves manufactured using heat and will tolerate these temperatures.

Plastic egg cartons should be washed in the kitchen sink using a mild anti-bacterial dishwashing liquid, then rinsed and allowed to dry completely before use.

There is little point disinfecting an incubator if valuable eggs are being stored in contaminated cartons.

Dirty eggs

The cuticle is the egg's first defence against outside agents.

Abrasion removes the cuticle and creates fine dust, which can itself block pores. Washing dissolves the cuticle. Washing therefore carries greater risks than careful spot-cleaning.

Whenever possible, improve nest hygiene and collect eggs more frequently rather than relying on cleaning eggs afterwards.

If eggs must be washed, remember these rules:

• Washing water must always be warmer than the egg.
• Warm water prevents the egg contents from contracting and drawing dissolved contamination into the pores.
• Wash eggs only immediately before incubation.
• Use a mild disinfectant. A mild anti-bacterial dishwashing liquid is preferable to harsh bleach solutions.
• If washing many eggs, change the water frequently.
• Light soiling can be rinsed under a warm running tap immediately before incubation.
• Avoid wiping eggs with a wet cloth, which tends to smear contamination into the pores.

The commercial approach

In the wine and cheese industries, the grapes or milk are sterilised and then inoculated with a known, desirable organism. This removes the risk that an undesirable wild organism will dominate the process.

Commercial hatcheries take a similar approach. Rather than gambling on which bacteria will win, they remove as much risk as possible by disinfecting eggs immediately after collection.

Ultraviolet disinfection

Top Hatch incubators incorporate a 254 nm ultraviolet disinfection system.

Use the ultraviolet lamp exactly as described in the instructions when placing fresh eggs in the incubator. Then use it daily, as directed, to disinfect both the eggs and the circulating air.

As embryos develop, they become metabolically active. They consume oxygen and release carbon dioxide, water vapour and other waste products into the incubator atmosphere. Good hygiene and regular disinfection help maintain a healthy incubation environment throughout the hatch.

Remember

An incubator will happily incubate pathogens along with our eggs.

Good hygiene starts in the breeding pen, continues through storage and handling, and ends only when the chicks leave the incubator. The battle for a successful hatch begins long before the eggs are set.