7 YO rooster not acting normal

[ffowl guy]

One of my boys has ashy comb, keeps his head down low and looks like he's got diarrhea. I recently treated for mites and bought some antibiotic that gets added to water. He still hasn't improved. The rest of my flock is good I have 8 boys, 4 who get to live with girls and the other four are 2 per coop and they are separated cause they don't get along. The guy that's his roommate isn't showing any similar signs. Any advise would be appreciated.

 

[Chick whisper]

Could possibly be worms. Before treating for worms, I would buy some electrolytes and put them in his water, if those don't work I would treat for worms. Hope he gets better!