I have 30 coturnix quail in a 7'x4' pen... I've started to notice that the girls are starting to purrr... and I'm starting to notice a few of them missing head feathers. Is this just normal behavior, or do i need to split them into different groups? I'll have three of these 7x4 pens when I'm finished, but I also have 30 butler bobwhite eggs on lockdown... any recommendations of how to spread out my birds? Or do i need to start building new pens?