Yes...many many years ago a breeder friend had almost 100 lovebird babies with polyoma. I quarentined them all in my garage against my vets advice, and tried home remdies and managed to save 75% of them. After weaned they tested free of the polyoma.
Can you detail more with the type of bird, age, symptoms, etc?
The most important thing is when the babies crop slows down to empty and flush it. If you can get Dent-a-gene from the vet this will help. The additive of it in the water (a couple of drops each feeding) helps to arrest further damage. It is the secondary bacterial infections that will kill the baby before the polyoma does. Are you on the Holistic Bird mailing list? I beleive about 10-12 years ago I had some postings on things I used, and they may be in the archives.