We have about 15 finches in one cage. All of a sudden we have some who has the back of their heads bald. All the feathers are gone. Is a male attacking them?
Zebra finches have a tendency to pluck their cage mates. There are many different theories about why they do this, but in your case probably the best answer is yes, they are getting plucked by other birds. There is a pecking order with each flock of birds, and these birds may be on the bottom. When zebra finches socialize they will often preen a fellow bird across the back of the neck and under the chin. This helps strengthen social bonding, however, this preening can escalate to plucking for attention, or to assert a birdís dominance. Most finches that are plucked are under a good deal of stress, which can weaken the immune system and lead to illness. It might be good to get these birds checked out by an avian vet. Or if you can, you could remove the plucked birds to a different cage for a while to observe if the feathers grow back, and see if other new birds start getting plucked...you might have a bully in the flock! Also, I donít know what size your cage is, but finches kept in a large free-range aviary in even pairs don't usually pluck each other.