I have given Tylan 50 (tylosin) in shot form with no problems, but just give it by mouth--very simple. You may have mycoplasma G, or one of the other diseases. Look at this link for diseases for symptoms and treatments: http://edis.ifas.ufl.edu/ps044
Corid is for coccidiosis only. The Tylan 50 would be what I would use since it may be the start of a respiratory disease. If she is large fowl you can dose her 1 ml daily for 5 days either by mouth or for 3 days as a shot into the breast muscle (alternate sides each day.)