Respiratory Issue In Flock of 10

[27strong]

I definitely know its respiratory issue in my chickens. I can't tell if it is spreading or not. Because there is no discharge from eyes or nostrels. What is really throwing me off is that one day a chicken sounds like that predator in the movie the next she is fine. Now I got another Hen weezing and she never weezed the day before. So it comes and goes. Evident and no so much.
The actions I want to take is add antibiotics to their water. I looked at Tylon and it is too expensive so I got something else. Its called Tetroxy HCA-280. In the back it has section for chickens. I believe my birds have some form of Myc going on contagious or not.
here is my question if I do have healthy birds mixed with sick and i put antibiotics into the water will it be bad healthy birds? If any1 has experience with tetroxy reply.

 

[Harry Rooster]

I don't know anything about the antibiotic you mentioned, but the one I am using sounds very close to it. I was advised by a vet assistant that has chickens himself, to give all my chickens the antibiotic Tetracycline/Duramycin (got from the feed store), just in case they may be infected and not yet showing signs. He recommended that I do this to protect the whole flock, cause most respiratory infections are very contagious (he said), also some on here have said so. I'm new to treating my chickens, since I haven't had problems like this until we got some new chickens, and my rooster got sick just from talking to them through the fence. Now I'm treating him, also and lost 2 pullets before I knew what to do. Hope this helps. Just thought I'd tell what I was told since no one has responded yet to your post.