I'd vote to keep #4... good looking, and will throw fertile eggs that could hatch out larger bred chicks... equals larger eggs for future hens and more meat out of future cockerels.
Everyone seems to be leaning towards #4 the mystery bird and I think so am I. I have a tendency toward dark feathered birds. Maybe he is a black sex link rooster? I might keep one of the 3 hamburg's too, they are so pretty!
And I don't think the turkeys are plucking out the roo's tail feathers, my turkeys and chickens completely ignore each other and they are all pasture raised, so the turkeys go one way and the chickens the other. I have had this happen before with chicks from Ideal.... They do eventually come in. Eventually. I raise them on gamebird feed, wonder if that has anything to do with it?
I guess it would depend on what you wanted to keep the roo for. The Hamburgs are by far the closest to any breed standard and would be my personal choice to keep but I keep birds that we can also show in 4-H and sanctioned shows at our local fairs.
Is number 4 primarily blue or primarily black? It's hard to tell from the pic. Also, I believe most black sex link roos are barred. Is it possible that he is a black (or blue) copper Marans?
You got those birds from Ideal? Seriously? Was this some kind of grab bag sale? How did Ideal know they were selling mutts? My mind is whirling. Curious over how Ideal described this mixed box. Wow. So curious.
I also would keep the little Red bird and see how it matures, if I kept any.