Respiratory infection without snot?

[Calafragalistic]

I have two hens. One has Loud wheezing labored breathing no snot, no sneezing, no coughing no foul smell and no other outward sign of illness.
The second hen sneezes, coughs and has gurgling rattling breathing, no snot, no smell, and no other outward sign of illness.
Both hens are a bit lethargic but are eating and drinking fine.

I've had them on tetracycline for a week via water and no change so I've now been injecting them with tylan 50 via the breast muscle.

They are large heavy breed full grown hens I have been injecting 1cc.

I have also been supplementing their water with electrolytes and vitamins.

Still no change on second day.

How long does Tylan take to show improvement?
If they don't improve by then what other antibiotics are there?
Any ideas what they are actually sick with???

Thanks in advance

 

[Eggcessive]

Respiratory diseases can be caused by bacteria, mycoplasma, viruses, and fungus (aspergillosis.) Only bacterial and mycoplasma infections are affected by antibiotics. Those would include MG and coryza which may be treated with Tylan, tetracyclines, and erythromycins. Other broad spectrum antibiotics may be needed for E.coli or others. Viruses and fungal infections will not respond to AB's. Infectious bronchitis and ILT are viral illnesses, and will have to run their course over several weeks. You may want to get them tested by your local extension service or through your state vet.

 

[Eggcessive]

Here is a good link about respiratory diseases and symptoms: http://edis.ifas.ufl.edu/ps044