What's going on here?

[TheYoungV]

A couple of months ago one of my cockerels developed a swollen eye after fighting with another cockerel, so we thought he had an injury. It lasted a few days and went away. Shortly after that we noticed what sounded like wheezing coming from him... Then more recently one of our other cockerels made a wheezing noise after he crowed. Coincidentally someone told me they were dealing with mycoplasma and the symptoms rang a bell... I put all of my chickens on oxytetracycline purchased at tractor supply for one week. I put 5 teaspoons in a gallon of water as per instructions I found on here in an older thread... Now my original cockerel still has the wheezing as does the other cockerel when he crows, and I haven't noticed any improvement. But they seem totally fine otherwise. It's been a while since the first cockerel developed the swollen eyes... He's totally ok otherwise but why didn't he improve with the antibiotics? Should I have put them on it for longer? Could it be another issue? Should we put him down? We don't have the heart to, but if there's no other solution we will humanely euthanize him. Thanks in advance.

 

[Eggcessive]

Many respiratory diseases are chronic, can come back whever there is stress, and they can make other flock members carriers which can keep the disease actively infecting new chickens. Treating with antibiotics only affects bacterial and mycoplasmal diseases, and some diseases are viruses or fungal. Things like bronchitis or mycoplasma can be complicated further by secondary infections. Many sick birds will not drink enough medicated water to get the right dosage. Most people with commercial chickens or breeding flocks will immediately cull any bird that shows symptoms of a respiratory disease. Some backyard flock owners will try to treat the symptoms, but must close their flock untill all of those birds are gone. Most respiratory diseases are not a problem after a few weeks when all birds are gone. I would recommend getting a couple of virds tested for what they have, or if one is very sick, put it down and get a necropsy by your state vet or poultry lab. Here is a link about symptoms of the common diseases and another to contact your state vet:
http://edis.ifas.ufl.edu/ps044
http://www.usaha.org/Portals/6/StateAnimalHealthOfficials.pdf