I have a 3 year old Silver Laced Wyandotte that has slept in the nest box since she was old enough to get in 'em. I agree with Zoo, it hasn't hurt anything just makes the nest box messier and they need to be cleaned more often, I too have to clean them everyday. I have about 6 birds total that sleep in their nest boxes just like Zoo, the 3 year old gal, a 2 year old rooster and the others are youngsters about 4-5 months old. The roo throws a fit if I take him out and put him on the roost when I go out to put the chooks to bed. As soon as I shut the man door on the coop, the rooster has made a dive bomb off the roost where I just put him and I hear him jump back up to the nest box. He also fluffs every nest box after I clean them......he's a weirdo.