Here are the answers I can provide, aart.
1. Welsummer rooster, 6 months old, I have no idea about his weight. He looks about the same size as the hens who were in his age group except he's taller.
2. He seems lethargic. Normally he would be very active and run to me when I come out of the house (looking for treats with his girls). He does free range in the yard but he seems slower than he was than he was a week or two ago. He used to crow all the time but now he rarely crows--but he does still have a hearty crow.
3. I noticed it about two weeks ago, but that was when I had already been distracted by dealing with a serious illness in our family, so I may have missed the first symptoms.
4. No other birds are exhibiting those symptoms. He has three hens and six pullets in his harem.
5. No bleeding, injury, or trauma that I can see; although, I have not examined him closely.
6. I have no idea what may have caused this.
7. He has been free ranging and picking in the grass and dirt but I have not had time to watch him very much so have not seen what he's eaten. He gets the same feed as the girls.
8. Have not been able to observe his poop as I work full time and have had too much going on to take time to observe, due to recent events.
9. No treatment yet. Did not want to do anything until I had an idea of what the problem might be.
10. The last time I took a bird to the vet it cost me $300, and she died anyway. It will be home treatment or no treatment for this bird.
11. No pics.
12. large, weatherproof coop with no direct wind on the birds but with good cross ventilation. The birds sleep on a roost (all on the top bar). The coop floor is deep pine shavings.
I hope this helps.