I have a chicken that is sneezing as well as a chicken that was fine one day and walking only on her "knees" the next and now she is close to death.(My 8 year old son is in tears). The two chicken issues seem totally unrelated. I don't know what to do. Do I get an antibiotic and treat the whole flock? If so, are they sold over the counter at my local feed store? Should I routinely be deworming the flock also? I had chickens before and never had these problems. Now I want to be proactive. I can't afford to take a chicken to the vet everytime I have a concern. What is the best way to prevent these issues?