None of the hens seemed to be broody at the time. And so far, when my hens do go broody, the others don't tend to bother them - they either use a different nest box or just sit on top of the broody and lay their eggs. But, so far, no fighting like what happened this time.
So, one of my speckled sussex girls was attacked while in the nest box - blood and feathers everywhere. Looks like one or more of the other girls went for her comb and just beat the crud out of her. The attackee has since been removed to a large dog crate so we can treat her (clean her up...