No, he is not sick, although he might be a little bored, he is just changing his old feathers. Try to spend more time softly talking to him and ruffling his head feathers to calm him down. If he starts plucking out his feathers a lot, contact a vet without hesitation.
Your bird could be suffering any number of ailments, from a cage mate who is plucking it, to French moult. If you have ruled out that another bird is plucking the feathers, take it to an avian veterinarian to help uncover the cause.
Many species of birds, including lovebirds, do something called "molting," which means losing their feathers, then growing new ones. Adult lovebirds do this usually twice a year. It's normal and nothing to worry about, unless your bird seems to be plucking its own feathers out and digging at its skin, which could mean it has a skin problem that needs to be seen by a veterinarian. See the Related Link below.
no it will die from fin rot
Yes, over time, but the tail feathers shoul NEVER be cut. You could hit a blood feather and really hurt the bird. If the feathers and being pulled out by the bird, this is feather plucking and should be looked into (may be a sign of stress). If your parakeet is having the feathers fall out because of the side of the cage you may need a bigger cage or move the perches so the bird doesn't touch the side.
Feather Plucking, Sleepiness, Crusty Beak, Not Opening Their Eyes, Falling Down, Not Eating Or Drinking.
Well, preening(grooming) and plucking feathers is a normal bonding ritual that many birds enjoy in the wild. You do not need to to put an end to this unless the male is making his mate lose a lot of feathers. If that is happening, consult a vet, because your pet may be stressed.
One of the other birds is plucking them. They may stop on their own, but birds tend to attack anything that is different about another bird.
The most obvious symptom of a bored budgie or cockatiel is feather-plucking. Parrots in general are among the more intelligent of the bird species, and they need activities to keep them stimulated. If activities are lacking, they resort to feather-plucking, pulling out their own feathers until they look bald in places. This problem is easily alleviated by giving the bird lots of attention, and providing a variety of toys, especially bells and climbing frames.
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.
Budgies can't pull out feathers that they can't reach with their beaks. If a bird is losing feathers on its head or neck, the problem is not plucking (unless a cagemate is responsible for the plucking). Bald spots are not normal for budgies, even elderly ones. You should consult an avian veterinarian.
plucking,ploughing,cattle grazing
Well, usually an African Grey may pluck its feathers because it is bored (they do tend to get bored of toys, which could be why it would be bored, all birds do). Or it may be stressed, you do have to spend lots of time with African Greys or they will pull their feathers out. If none of this advice helps, you might want to ask a vet.