Good luck to you and odin! Cute name for a real cutie of a chick.
When using antibiotics, just like with us humans, it causes a resistant bacteria. Perhaps the bacteria that is causing an infection needs to work through, or the chicks immune system needs to kick in.
I personally had a necropsy done on a hen, one of my faves. Let me give a bit of history, when I recieved this hen she had an eye issue, kinda heavy breathing wheezy. First thing I did was Tetracycline. She came up with a stuffy look, gave her tetracyline for CRD, that 99% of us have in our flocks.
Heck if she coughed, I'd put that in the water for all the girls, if its good for one, its good for all of them...(not as much as I sound but close)...Kathleen, my little show quality blue cochin went broody, began to cough, refused to eat or drink. I put some Tetracycline in the water and spooned it to her, she was in rough shape.
I culled her, sent her to the UMO for a necropsy, and what did we find out...the pneumonia that Kathleen had was resistant to tetracycline.
Please, do not use antibiotics if you do not have to. For animal or human. Why is it that we need so many OTC drug for a common cold when we can use 1/2 strength (my mom uses childrens) to take the edge off something we need to become ammune to.
Sorry to have taken of on your issue, and for your birds health, I am not against antibiotics, but if it can happen to me, it will happen to you, save it when its a major issue.
I am glad you are trying some of the alternative remedies first.
Personally, I need to start having that cup of tea during the day, cure my bout of crabbiness!!!!!!!!! Have a good day!