My hens are about 25 weeks old and started laying in late August. We have 6 hens & 4 nesting boxes. Often I'll find 3 boxes empty and two hens - one on top of the other - in one nesting box. Is this typical? Is it dominance behavior? Or just a favorite box? I'm assuming it's not a problem but would love feedback as I'm new to all this chicken stuff. Thanks!