one of my chickens has spots on her comb that looks a lot like fungus. i could sort of scrape it off. i've had her on a antibiotic for a while but its not helping and the lumps are getting bigger and burrowing into the skin. i need an antifungal but i can't get nystatin since its prescription only. and right now i can't afford the huge vet bill that will come with the chicken. i just had a huge vet bill because of my rabbit and can't afford another one for a bit. is there any antifungal i can use on her? besides nystatin? please help.