All birds lose their feathers,so your answer is that all birds do.
Disease - birds do not normally loose their feathers. When they change them it is called moult.Moulting is a process (like shedding in mammals) done regularly by birds, to replace old feathers with new, healthy feathers. This is normal. When a bird loses many feathers at once, it is usually due to the bird plucking out its own feathers OR a condition called French Moult, for which there is no cure.All birds may or may not lose their feathers. It is only when this happens to them and or they die.
how the feathers protect the bird
As far as we know, there is no bird living without feathers.
how the feathers protect the bird
It will not be able to fly with no feathers. Feathers keep a bird warm. If its feathers are gone it will die of cold. Most importantly feathers help a bird to escape from predators.
Another name for bird feathers is down.
Down feathers are feathers that lie under a birds body and primary feathers. These feathers are small and puffy, and trap warm air under a bird's feathers.
Feathers that are on the neck of a bird.
either molting or (and this is a joke. not for real.) DEATH! ha i really think its molting. a bird loses its feathers to grow new ones. it usually happens during winter to a bird that doesnt migrate and needs to be camoed. Hope it helped :)!
Bird bones because feathers are very light and the bones just depend on the type of bird.
we are asking is there not a baby bird with yellow veins in its feathers
if it has feathers