I have two Isa Browns they were great with the six Easter Eggers that I got about 2-3 weeks after I was given the Isa Browns. Just now that they are coming up on their first birthday I'm having a problem with them pecking at the dark feathered EEs. I have witnessed them doing it and the hens have bald circles above their tail feathers. I am using a product now that seems to be working and in the spring I'm going to increase the size of their coop even though it is adequate for the 8 hens that I have. I know that when I hand feed them worms the IBs always bite my fingers. But I'm pretty stubborn and feed the EEs until the IBs will take the worms nicely. I swear they are smarter then we give them credit for.
Michael, I suggest you do a little research on the ISA-Brown hybrid poultry. There is a lot more to them than what you seem to think.Isa Brown is one of a number of labels under which some hatcheries market their Red Sex Links which are produced by crossing a red gene rooster (RIR, NH, or PR) with a silver gene hen (RIW, SLW, LS, Delaware, or silver factor WPR). Not only can the offspring be sexed by color (male chicks are whitish, female chicks are reddish), but they are egg laying machines (300 + eggs per hen per year) outlaying either parent breed. It's one of the interesting quirks of hybridization. Isa Browns are fairly good foragers when free ranged and are generally docile and will mix well with other breeds as long as they are not overcrowded. If you're wanting sex links, in my personal experience with them, I actually like the Black Sex Links (Black Stars) better. My BSLs have been friendlier than my RSLs (Isa Browns), have laid just as many eggs per year, have generally had a longer laying life, and have tended to be more persistent layers in really cold winter weather than my Isa Browns. Of course there can always be exceptions with any breed or hybrid. Hope this helps.