FERTILITY OPTION 2:

hatching eggs

Hatching eggs are a great way to introduce a new breed or bloodline into your flock.

The chicks that hatch will naturally develop an immune response to diseases on your property, compared to chicks you buy. Brought-in chicks may also carry diseases you don't have onto your block.

Ask the breeder about the fertility rate and potential hatchability of the eggs you want to buy:

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fertility should be 96-98%;

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hatchability is usually 4-6% below the fertility rate (due to losses during incubation).

Different breeds have higher or lower hatchability rates. Storage, transport, and incubation fluctuations can also influence the final hatch percentage.

4 tips to finding a good breeder

You want someone with:

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a good reputation for high hatchability; •

birds that are up to the breed standard in looks;

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birds with high fertility;

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a clean, well-managed property;

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healthy-looking birds.

If you want to invest time and effort in purebred heritage breeds, it's worth attending a poultry show. Shows take place in autumn and winter around the country. Talk to breeders and get their advice on bloodlines and breeding.

Ask about the health history of the birds, eg vaccination status, worming regime etc.

How can eggs all hatch on the same day?

A hen can only lay one egg a day, so evolution has come up with a brilliant way to ensure a clutch hatches on the same day.

Once laid, a fertile egg cools down over about six hours. Its internal temperature reduces from around 40°C to 12-20°C, and development of the embryo ceases. It can then wait in suspended animation for 10 days or more until it's triggered into growing when the egg temperature goes above 26°C.

This means a hen can lay an egg a day for 5-10 days to create a ‘clutch,' but she doesn't need to start incubation (and raise the temperature above 26°C) until she finishes laying the last one. All her chicks will then hatch within 24 hours, around 21 days from when she starts sitting.

If eggs are left in a nest on a hot day or under a broody hen and stay at around 35-40°C, embryo cells will continue to grow past the stage where development can be suspended. Any subsequent cooling then kills them.

In this case, the egg will appear to be unfertilised if you candle it. If you crack it open after the other eggs have hatched, you might also think it was unfertilised. However, it's possibly a very early death that's not detectable.

Can you hatch a double yolker?

A double-yolker is an egg created when two yolks are released simultaneously by a hen's reproductive tract. They're more commonly produced by younger hens, as their bodies are still settling into a 24-26 hour laying cycle.

There are rare cases of twin chicks hatching, but usually either one chick will suffocate in the shell while its sibling is hatching, or both die as they're unable to orientate themselves to the air cell for pipping. Chicks might live if you help them out of the shell, but it's risky.

If you have a bird that persistently lays double yolkers, don't breed from her. Double yolk eggs are more likely to cause prolapses, which are very painful, and can kill a hen.

Pity the hens that have laid some of the world's largest eggs, weighing between 195-200g in various countries. That's more than three times the weight of the average single yolk egg (58g).

There are rare cases of twin chicks hatching but it's very risky.