ditto. i wouldnt worry about a little bit of fighting if theyre not injured more than some scratched on their combs and its not constant. it seems the combs are the first target in chicken spats, at least around here anyway.
Agree - about the only intervention I might make is to give them something to do - I read recently about making cakes for them to eat, from seed, grains, crumble, oatmeal, wheat germ, coconut oil, I'm sure you could add any number of things, but then you press it into an 8x8 pan (although at the time I thought it might work better to use muffin tins) - the writer mentioned putting a hole in it so it can be hung, but you might also bake in a piece of wire to attach to a run wall or roof. You bake it *I think* around 250 degrees for a couple hours and then cool. I'll have to see if I can find the recipe again.
Anyway, giving them something like that, or a cabbage head hung, or a turkey carcass, really anything they can work on for a while. Winter boredom leads siblings and flockmates alike to squabble.