Bacterial synovitis - duration of antibiotics?

[Glendaroost]

Hi everyone, I have a lavender orpington that I've posted about in the past. He is still a bit of an enigma prior to our vet school appointment, but I have a suspicion that he has bacterial arthritis/tenosynovitis complicated by reovirus due to his stunting and poor feathering. I was wondering if anyone had experienced a young chicken with bacterial arthritis and how long you treated with antibiotics for? I believe I caught it reasonably early although after 10 days of tylosin injectable, about 5 days later he had similar signs again and he is almost back to square one. He is bright and eating/drinking otherwise, but still has poor leg strength.

 

[ChickenCanoe]

Are you saying you haven't taken him to the vet school yet? Which vet school?
So you have no lab work to confirm your diagnosis of the presence of mycoplasma synoviae.
I'm not surprised the tylosin didn't yield the desired effects since there is no effective treatment and survivors will be carriers.
Is this an extremely valuable rooster for some particular reason that he couldn't be euthanized and replaced with a healthy animal?
Treating anything with antibiotics without a true diagnosis is dangerous.