DJ is a normal male, almost 1year old. He was quarantined with his girlfriend for about 6 weeks in a small cage. Because of that size, his tail feathers did get somewhat ratty

It seems to me that everybody gets along very well, most of the squawking and chasing is the zebras between themselves. very little intraspecies aggression, though I do work full time, so I'm not always there. DJ is without doubt the least active bird in the cage. I mean, somebody has to be, but it seems quite a gap. he does the least flying, preferring to climb anywhere he wants to go. he can fly, just doesn't seem to want to. He has fallen several times trying to climb up or down. He still sings, eats well, doesn't seem particularly fluffed, stays near the top of the cage.
If he is molting, would that account for the decreased flying and activity? his girlfriend had no trouble adjusting to the large flight.
sorry for the length, just trying to fill in all the details! thanks!