My cock looks after the chicks in the flock too and breaks up bullying. It's normal for them to do so, but it depends how your flock is managed, as to whether the cocks acknowledge the chicks as "part of their flock" or not, since chicken socialization is a complicated thing--or, you could just have a dumb roo too. Most recent breeding efforts have not devoted much care to selecting for appropriate natural behaviors like that (such as appropriate mating behaviors, foraging ability, socialization skills, setting and mothering skill, predator awareness)--the instinctual intelligence of our poultry stocks is getting waterered down or eliminated completely in some cases... It's important to keep breeding back in these things.
For that reason ALONE I will be keeping this cock in my breeding program as long as possible (never mind that he is a mutt that doesn't meet any breed standards)!
Sorry about your incident! I hope the little cruiser recovers well!