I have had my older jumbo coturnix's in the same cage since the day they hatched. No problems whatsoever. They are in a 2x2 cage, there are 3 females and 1 male. This morning when I went out to feed them, one of the females has part of her face gone!!
I can't tell if she actually lost her eye, but that seems to be the focus of the attack. What gives? These guys are about 4 1/2 months old, and I haven't had any problems with fighting.
