Thanks, but how do I break her from sitting? I have tried removing her from the nest all day. At the end of the day she will go back to her nest. She is rejecting the fertilized eggs I am putting under her. She has been in this ordeal for about a month or more. I am very worried.
The physiology of brooding involves a looping circuit. When her breast is in contact with the eggs or nest, it stimulates a nerve which causes production and release of the brooding hormones. This causes her to remain in brooding mode, pumping out heat through the metabolism of her stored reserves to brood her clutch, being miserly with her feed intake, etc.
Breaking that circuit stops her brooding. A day is not enough of a break for most hens and it's especially unlikely to work if she's able to sit and rest somewhere comfortable/warm and keep that circuit going. In order to break her off the brood properly it helps to put her in a cage that has some elevation above the ground and a mesh or wire bottom so she will have cool air on her breast, not a warm nest. Two days of that should break her. It helps to put her in a bright place, so she's not feeling secluded and secretive, lol. Of course she needs shelter from the sun, rain etc but four solid walls are unnecessary.
But, some hens get mentally bent on it and cannot break out of the brood; with these there is probably a hormonal dysfunction causing them to remain in that state no matter how many eggs hatch under them. Some break out of the brood within minutes of leaving the nest to take a drink, eat, whatever, so they naturally do not become mothers unless humans intervene and then they make terrible mothers because they are uncommitted and keep reverting to non-maternal state; these hens probably have a shortage of the hormones required. Some take longer than two days to break out of it.
We've bred maternal instinct completely out of some lines, it remains incomplete and partial in some, and resurrecting it is an imperfect art so you get many 'duds' along the way, who have one portion of the spectrum of maternal behavior and instinct, but lack any one or many of all the other elements required to be good mothers. The same is true of roosters as fathers, and all social mechanisms, the instinct levels vary wildly.
I had one hen who would not break no matter what I did, so when she had degraded too far I called it quits and culled her. There wasn't anything else to do, she was nonstop broody for over 6 months and close to death, she'd lost her sanity and health long ago despite my constant efforts. Physically she just could not stop, it's not unheard of, hens die when they can't stop.
The big issue there was that she was a terrible mother so there was no natural conclusion for her, she'd abandon her hatchlings every time and go find more eggs to sit on. I've seen quite a few hens with that 'glitch'. Many hens have the instinct to brood but not to mother, and will simply abandon or destroy chicks to go back to brooding. Some hens even have the instinct to mother but not to brood. Never trust an untried mother, too many people say 'let nature do her thing' and disasters ensue. Domestic animals do not represent natural instinct, lol!
Anyway, best wishes with her.
