Poor little girl. She has been through it, but it does look a lot better. The antibiotics must be helping...which means I'm back to MG/CRD too.
That can be bothersome stuff. Some birds get a one time mild infection, then seem to thwart it off for the rest of their lives, although they are still lifetime carriers. Some seem to flare with every change in the weather or new stress. Keeping life stress free and their immune systems built up can do a lot, but industry has resorted to feed additive antibiotics as MG can be so bothersome and the NPIP program is stressing MG free breeding flocks and layers to help control. There are also vaccines available, with varying protections.
From my research, Tylan (Tylosin) and chlortetracyline (Duramycin-10) or oxytetracyline (like Terramycin or Tetroxy, which has been recently approved as a feed additive) help control CRD. MG can be something you will need to treat and re-treat periodically for a susceptible bird. And you have to be aware that all new birds will be exposed, and of course you'd have to keep a closed flock (which it sounds like you don't sell or show anyway).
If you were selling eggs or meat birds, you would need to consider FDA approval for antibiotics, which is very restricted for laying hens. Since MG passes through the hen to the embryo, any hatching eggs could be infected. If you were to show birds, you would have problems as your birds would have been exposed and could be considered carriers. If showing is something you want to do, it would be necessary to have a vet formally diagnose this since until then, you are only guessing at what it could be from the symptoms.
But it doesn't sound like you are selling eggs or meat birds or showing, so you then don't have to worry about FDA approval or exposing other birds to your birds since you purchase and keep them as your hobby...use what is safe and works using rule of thumb for pull times for eggs of generally 10 to 14 days after last dose.
Links for antibiotics that help MG
http://articles.extension.org/pages/66981/antibiotics-approved-for-use-in-conventional-poultry-production (scan for Mycoplasma)
Edited by Lady of McCamley - 1/9/16 at 6:11pm