(french moult)(budgie fledgling disease/virus)(polyomavirus) budgies have no tail or wing feathers.🤔

The parent birds to these 2 chicks have been in my big cage with all my other birds for 2 years now and have always
appeared healthy along with all the other birds. This is making me think that these parent birds are carriers of this virus and have passed it on to 2 out of 4 chicks. This year i had 6 breeding pairs all of which had healthy chicks apart from 1 breeding pair. before i start in no way do i claim to be an expert on this subject. This is information i have found in my search of the polyoma virus in birds. There is alot more information on this virus that i have not covered. Including what i think are french moult horror stories as french moult can effect more than just the birds feathers. french moult is said to be contagious but not normally passed on from bird to bird. french moult is said to be transmitted to birds through a parasite which has contaminated the water or poo. It is usually passed on from parent bird who is a carrier of the virus to the chick/chicks. not adult to adult. hence the name (budgie fledgling disease). Passed on to the chick through the egg ( genetic mutation ) only 2 of my chicks from a clutch of 4 have signs of french moult . french moult is a feather disorder that can leave the bird unable to fly. They can suffer missing feathers deformed feathers and it also effects there growth . making them stunted. so they appear small and plump. Effected feathers are mainly primary wing and tail feathers. Feather growth is slow if at all. They might grow feathers but they will soon fall out. fench moult is said to be non life threatening. it does not cuase pain or suffering and a budgies life expectancy is said to remain normal. The budgies immune system to this virus also plays a vital roll if they survive or not. Budgies with french moult will need some extra care as they can not fly . i will be setting up a special cage for my french moult chicks which will have ladders leading up to perches and low down food bowls . There is no cure for this virus so i will not be breeding this pair of budgies next year.