How do chickens “sync” their eggs?



I’ve seen friends post photos of chickens who disappeared and come back with a clutch of chicks. Assuming one chicken, laying one egg a day, how does a broody mom come back having hatched 3-5+ in a given cycle? Do other mothers sometimes contribute to a clutch, too?

Do they hatch progressively or sync up a bit, does the mother hen manage the eggs to get them all the same “amount” of incubation as to have them hatch out nearly the same time?

In: Biology

A hen can lay a clutch (5-7) over a few days. They rotate the eggs in and out of the center to evenly heat them, so slow/quicken the development.

So I have a hen who’s sitting on some now. A Hormonal change in the chicken is triggered by a few factors. Increase daylight, seeing or hearing other chicks, and watching a clutch of eggs accumulate all factor in. The hens lay eggs for a few days, then one hen will decide “I’m ready to be a mother now”

She then will sit (if she’s committed) the 21 days till they hatch. She will start incubating them all at the same time. Sometimes hens will continue to lay after she’s started sitting. In those cases those chicks are delayed by a few days. Once the older chicks hatch the hen may sit for an additional day or two, but after that she’ll be done.