Please explain how chickens keep laying eggs even without a rooster. And are all birds like that?
In: Biology
No.
We have selectively bred chickens for thousands of years – ie, we choose the ones that lay lots of eggs, and breed those.
Typical birds lay about 3 eggs per year. It varies a lot – some types of duck will lay 15 in one nesting cycle. But our chickens can lay hundreds per year.
Any bird (female) can lay an egg without a male. I had a cockatiel who would and she didn’t have a mate.
Chickens have also been bred to produce a *ton* of eggs in a constant stream. The red jungle fowl, which is the bird chickens are bred from originally, will lay about 7 eggs twice a year. Total of around 14ish. There is a good reason for this, since fertile eggs wait to start developing for up to a week until the hen regularly incubates them. This allows the chicks to hatch at close to the same, and you don’t have chicks strung out in age and size (they grow very fast,) that the hen has to care for. People regularly order fertile eggs through the mail that capitalize on this pause in development.
Somehow, we figured out how to breed them to produce nearly an egg a day for the first couple of years of their lives. A very useful trait. A few hens can keep a family of 4 in eggs for the year surviving just on food scraps and foraged food. Back before modern farming, eggs could be the majority of someone’s protein intake.
Chickens are domesticated versions of Red Junglefowl (technically still the same species!) native to SE Asia. Bamboo there flowers/seeds on a multi-year cycle, so every several years the ground is COVERED with seed. These birds have adapted to go absolutely nuts when this happens, eating a ton and making/laying tons of eggs.
Domestic chickens have this “switched on” all the time, because we can feed them lots of food all the time.
You can compare laying eggs to menstruating… I’ll happen with or without a rooster.
But the only reason chickens keep laying eggs is because we remove them every day. Take it from my small chicken coop – if the eggs are left then the hens will stop laying eggs and start incubating them… And they won’t start laying eggs again before the chickens have hatched and are big enough to fend for themselves… Just like a woman usually wont start menstruating until her baby is weaned…
I can also tell you that hens don’t usually lay eggs in winter – and go nuts in spring… I would actually suspect that all birds have those traits.
The industrialized hybrids might not show the same behavior, but that’s because we have ruined them. Normal chickens lay way less eggs in a year, but grow to be 8-10 years old, without ever stopping to lay completely… hybrids have a ray of health and behavioral problems – and just seeing them hurts my animal heart…
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