Not really. If you decide to treat something respiratory, provided you can determine it is NOT fungal in nature (antibiotics make those worse), Tylan would be preferred. Tetracycline is very weak stuff.
I would never treat contagious respiratory stuff because most of those diseases leave them carriers, like a Typhoid Mary in your flock, some being herpes type viruses. ( I would separate symptomatic birds, determine if they are contagious, have pneumonia or a fungal illness, then if contagious, euthanize).
Unless you have testing, you can't know if they have bacterial or viral, and as you know, antibiotics do not treat viruses anyway. Even if you treat, that does not change the fact that they remain carriers. Mycoplasmosis/CRD is the most common disease of backyard flocks and it is bacterial and leaves carriers, plus can be passed down through the egg to the chick.