If you are treating Mycoplasma, see if the pigeon supply still has this in stock, I'm not showing it sold out, but you never know.
https://pigeonsuppliesplus.com/products/tylosin-99-100-grams-pdr-pigeon-supplies-plus-line?_pos=1&_sid=cfca1c19e&_ss=r
As for the Doxy/Tylan, personally, if that's...