Mine do that. 2 months old, mum laying again...I had to move her chicks out, because when she was brooding the new eggs, her chicks would go and roost in the box with her at night, and poop everywhere! (they´re free-range) She now has her newer chicks and the bigguns are off to new homes.Sample space of one, but my (incubator-hatched) Brahma has been a wonderful broody! I put 12 under her. 8 hatched (the rest culled as infertile or fairly early quitters), 1 died at hatch, and I now have seven vigorous, healthy 2-month-olds running about. She has been attentive and protective, and has just this past week decided she's over the molly-coddling and it's time to start introducing some training in manners(She has just started laying again, three eggs so far.)