Flagyl is the brand name we were given. The cheesy growths are a combination of ulceration and inflammation caused by a parasite called Trichomonas Gallinae. Unfortunately when the immune system is depressed they can rapidly take the bird over and it may be too late to save your friend's hen. The big problem though is it is transmitted via feeders and drinkers, so the rest of the flock will be carrying it and now need to remain 'closed', so none out and none in. I suggest treating the rest of the flock as well, but see what the vet thinks. If not treated now, the others will need regular inspection for small growths in the mouth at which point, based on our experience, they can be helped. Until you are certain none are carrying it the flock needs to remain closed.