Lbrad7 - I think you need a little more help from your hens
It was CROWS (big black flying thingies) not COWS (big black & white not often flying thingies) the OP was asking about.
Very Funny. First thing that made me laugh this morning
I'd say crows help more than they hinder, if you've got hawks or snakes.
Sure they might sneak a chick away now and then but it's more opportunist than actually hunting them. They do chase away, or at least alert you and your chooks to, hawks, owls, lizards, snakes and cats.
I'd rather have...