Incubation
Unfertilsed eggs laid by hens which have not been mated are produced for eating whilst fertilised eggs are used for hatching. Hatching can be done in either of two ways:-
- naturally by the hen or;
- artificially by using an incubator
- When the natural method is used a broody hen sits on the eggs until they hatch. Once hatched the hen 'mothers' her chicks and keeps them tucked underneath her wings to provide shelter, warmth and refuge in the early days of their life.
- About 1000 years ago the Chinese artificially hatched eggs. Today an oven-like apparatus with temperature and humidity controls is used.The effective embryo temperature for hatching hen eggs is 37.50C. The eggs in an incubator should be turned at least three times a day, however, these incubators are designed to do this for you.
INCUBATION PERIODS
The process of development from the fertile egg to hatching is essentially the same within all species. Variations in incubation time occur with different species and within different species of the same family group. There is variation within a species - the first chicks may hatch at least a day earlier than shown and the last over a day later.
Incubation Periods Days |
Average Egg Weight g |
|
|---|---|---|
| Quail | 17 |
9 |
| Hen | 21 |
55 |
| Pheasant | 24 |
33 |
| Turkey | 28 |
85 |
| Duck | 28 |
80 |
| Muscovey | 34 |
75 |
| Goose | 30 |
210 |
Incubation periods are affected by:
- Species: see table above.
- Breeds within species: the heavier the breed the slightly longer the incubation period.
- Incubation temperature: slightly higher or lower temperatures will speed up or slow down development.
- Age of eggs: older eggs take longer to hatch. Eggs 8 - 14 days old may take 6 - 10 hours longer to hatch than eggs that are 1 - 7 days old.
SELECTING EGGS FOR INCUBATION
Only eggs of normal appearance are incubated.
Eggs that are not normal in some way will give disappointing hatch results.
Do not use:-
- Very large or double yolked eggs.
- Obviously small eggs.
- Eggs more than seven days old.
- Very dirty eggs.
- Cracked eggs.
- Thin shelled eggs.
- Abnormally shaped eggs.
HATCHABILITY EXPECTATIONS
Remember that maybe only 80 percent of eggs will be fertile and perhaps only 80 percent of the fertile will hatch.
