Moulting is a normal part of a birds feather growing cycle, which means their bodies benefit from a little extra nutrition – see my other blogs for that. You will notice your budgie looks a bit scruffy, and feathers are falling out. Its normal, unless of course, there is baldness from losing (or maybe plucking) too many feathers. Moulting happens in budgies around 4 times a year, and 3 times for cockatiels.
When new feathers grow back, they will have a hard outer coating which breaks up and lets the feather out.
In the wings and tail, new feathers are known as “blood feathers”. That is because as the feather is growing, it is connected to the blood supply. Once it stops growing the blood supply dries up. If your bird snaps a blood feather it will need to be completely removed – preferably by a vet. It will be bleeding and will not stop until the feather is taken out. There are ways to stop the bleeding, by using flour (preferably corn flour) or styptic powder (from vets, pet shops) on the broken feather – but if the bird knocks the feather again, it could bleed to death quickly if you are not around to supervise it.