I think you're definitely on to something with the suggestion of stress. I separated him just last night and this morning so that he didn't have to worry about diealing with the other roosters before bed and before I let them out. When I did let him out, his comb was genuinely back to normal for the first time in days. I'm going to spend a bit of time today converting the shed so that I can use it as a time out place for chickens who might need a little quiet.
This is actually kind of convenient, as I need to work on the shed anyway. The "shed" is a 100(ish) year old wash house which is laundry on one side and proper storage shed on the other but with no genuine wall between - a space of about 1m x 2m open between them. I spent a good portion of yesterday chasing Grendel out of there who was sassing me and telling me that she was going to lay an egg in there whether I liked it or not, trying to walk right around me like I just wasn't going to see her or like I was just joking the previous 50 times I said, 'GET OUT, GRENDEL.'
She's probably mad at me for giving her a boy's name. I hope not, or I may end up with Gandalf and Brian Blessed plotting against me.
Good to hear. Just keep an eye on the purple comb. If he's been panting the lack of oxygen in his blood stream will cause this, I lost king Henry the LS at 12 months of age . He was a magnificent bird, I had noticed a bit of purple on his comb and then he died of what I suspected was a heart attack.
We had a great day at the show yesterday. I spent a couple of hours in the animal nursery fielding questions from people about my 'fairy floss ' silkies. Most common question, ' will that colour harm the birds in any way ?', closely followed by ' do they lay rainbow coloured eggs?'

The birds were very calm and well behaved, not bad being as they haven't had much handling, but they were glad to be home.