Cause I think the cock was starting to get tired of them. They started looking irritated. Usually I use broodies in their own cage and pull chicks at a day old. The few times I let the mommas set was just to let them hatch a clutch at the end of breeding season. The last was that single kelso chick and I let it stay with the parents long enough to not get a chill by itself in a pen. Only did that cause I didn't want a single chick inside in a brooder