Ive seen some pretty big nest boxes out there on you tube, I dunno if its just me, but most of the vids ive seen if breeding does, They are in these little cages with a nest box and have just enough floor to sit on the side of the nest box almost on top of the food, its like they barely got enough room to turn around in there,I just built a hutch for My preg. Flemish its 6 ft long 3 ft wide and 3 ft tall, and it still looks small to me, I gotta post pics, I think I did an awesome job, I used all new material and It only cost me 60$