My 6 month old roos have been shedding constantly for the last few months, but they look better than ever at the moment. They've even lost significant tail feathers, only to grow beautiful new ones in right away. I have been giving them starter food up until the last 6 weeks or so, when they moved in with their hens. From what I've been told here on the forum, it can be normal. If they look like they are pecking or feather eating, then yes, up the protein, and separate the culprits. I've had that situation as well, and turkey starter worked just fine for that extra protein boost for the short term. Now I'm supplementing with more treats like mealworms, so that I don't have that issue again.