I think the respiratory infection deal is all over the place --- there are so many people who are trying to get rid of it. I lost one hen Wednesday evening. I finally took 2 of the worst ones to my vet on Saturday --- I NEVER thought that I'd be the one to take a chicken to a vet -- but it was either that, or sit back & watch them suffer & die slowly. I had already treated for 10 days with 2 antibiotics. And like a lot of people, the results of that are: not getting rid of it--not getting much worse -- not getting any better. Anyway, my vet gave those 2 an injection (the stuff is used mainly on cattle) and it actually seems to be working. -- knock on wood . I picked up 15 more syringes of meds today and gave out 10 shots.... I will finish that chore tomorrow after work. I just hope #1 that it gets rid of whatever is going on & #2 that it STAYS GONE.
I talked to my vet about trying to find out what's going on -- his only suggestion to get to the source was to cull one of the sick ones & send her to the state lab. Cost is around $100, then if they have to start doing this test, that test, to pinpoint it, it costs more. So you're basically stuck with not knowing what's causing the problem.
This is my 4th year of raising chickens, and the first time that I've had ANY health issues at all.