Yes, his foot looks strange and a bit swollen. Gout I believe would affect both feet. That looks more like an injury or since he has had the limp from his youth, maybe a worsening of the problem. His poop is really bright green isn't it. That may be because he has not been eating enough. Can you feed him some eggs and put some yogurt in his chicken feed to make it more appealing. He looks to have beautiful lacing. What antibiotic did they recommend? I think he does need it. I hope you start seeing an improvement.
Gout in humans starts with one and quickly goes to the other. It is a chronic condition and managed with starches. Meat makes it worse. It is inflamed when you have a lack of these in your diet and is caused by acid in your joints. So, no I do not think it is gout. It may be arthritis, which can present in one or many joints.
I don't know for sure what the problem is, however I do have a suggestion for treating the symptom. Try a warm Epsom salt bath for the foot. Epsom salt reduces swelling and draws out infection if there is any. Reducing swelling can help with pain. Also, with less swelling you could feel if there is a noticeable injury.
If he's mouth breathing then a respiratory infection is likely although there are a few less common causes of mouth breathing.
Green diarrhea is often blamed on salmonella or E. coli. The former often does also infect joints and cause them to swell up aka infectious arthritis.
I think this is a good case for a fluroquinolone. It would be the ideal antibiotic if it's salmonella and there's a good chance it will take care of any bacterial respiratory infection as well.
well I didn't know really what to do so I took him to the coop and put him on the floor in a nest box. you think that will be ok or should I go get him? also is this ECOLI everyone is talking about can we HUMANS catch it? that's the biggest reason I took him out.
Green stools can be from many things--you probably shouldn't worry about it for now. They can happen because a chicken isn't eating much, or is eating a lot of greens. Yellow mustardly looking diarrhea can mean E.coli, or it could just be a normal cecal poo. All animals have E.coli, but in chickens who get certain infections, E.coli can contaminate the abdominal cavity and get in to the lungs and bones. Here is a site for info: http://www.aphis.usda.gov/animal_health/nahms/poultry/downloads/poultry10/Poultry10_is_Ecoli.pdf