Just read all above about the feather problems related with viruses.

Very excellent information.

I’m a rookie exhibition budgerigar breeder from Pakistan.

I got my initial stock from local breeders and bird market…the very first generation of birds were born normal feathered, but after moult they have stress bars on primary flights and primary tail feathers.

I have seen this problem only in males and their female siblings have strong feather quills and perfect feathers. Their feathers do grow at normal rate but with stress bars. Their diet and protein intake is good enough.

I don’t think it is a APV, French Moult or PBFD.

I’ve noticed on few males they have primary tail feathers like they chewed it early stage. I will try to post pictures.

Warm Regards,
Usman