That is odd that you have all cochins and are having this problem. There is a possibility that it's something else, but it does appear to be the same. Hmm... I'd imagine it may stress them a bit to move your rooster, but for the rooster, I'd say the condition of his feet are also causing him stress. The only way that I can think of to see if he's being pecked is to separate him by himself and see if he heals.
But I'd suppose you could try to put something on his feet that your hens won't like the taste of. But if that doesn't work, I would separate him. They don't like it at first, but they adjust.