Neversink7 asked, "...have you ever had problems with splendid or bourke parents pulling the feathers off of their babies?" His Splendid parents are misbehaving and he wonders if a nutritional deficiency could be a possible culprit.
I don't think nutrition of any kind would cause this. There are plenty of feathers available that fall off the birds naturally and I often see my birds "playing" with fallen feathers, as well as routinely preening themselves. They can chew on all the feathers they want to, so why take them from their babies?
I've never had Bourkes pull feathers, except for the incident with one pair savaging a baby. With that pair, I always rescue and handfeed the young almost as soon as they hatch. I believe the male wants to breed again and dispatching the babies will allow that. I recently put the hen on "rest" and moved the male to another hen whose eggs have always been infertile. She's now on fertile eggs and I'm interested to see what happens. I may end up handfeeding her young too, if this male is actually the "bad" parent.
[UPDATE: After the cock was successful with another hen and a good dad, it turned out that the mother of the brood was to blame. Although she could hatch her eggs, she would not raise the babies and would begin savaging them as soon as all the eggs hatched. I still have two of her offspring (a brother and sister) that were hand fed and are wonderful parents with their mates. Both are very sweet natured. Their mother eventually developed an odd "droop" and died a few days later. I've wondered if she had a brain tumor that made her crazy or something. Also, she was sold and came back to me after her first clutch with a different mate also died. I don't know what her history was for the two years she was away from me.]
My experience with Splendids is different. Many years ago I bought my 1st pair and the hen's back was bare. I was unfamiliar with Splendids, but didn't like the fact that the male pulled the feathers from her back. She was sweet and tame, but he was wild...drew blood the first time I caught him.
Their first brood died. They didn't seem to know to feed them. Their second clutch of three did fine and I still have a male from that clutch. He has NEVER pulled feathers from his mate(s) and neither has his son (the grandson of the 1st bird). None of my Splendids have ever pulled feathers from their young. I was happy to let that original bird go as a lone caged bird to someone else who enjoyed watching and listening to him.
To Neversink7: How many clutches have your problem birds had? I'd limit them to two or three, with a few months in between. Maybe they're tired of feeding and caring for their young...? Sounds like you are doing the right thing by pulling and handfeeding them.
Another thought ... if the young birds are fledged and able to eat on their own before the parents begin pulling the feathers, in the wild they would try to chase them off to live elsewhere. In a small cage or aviary, they can't leave. Is only one parent feeding and the other pulling feathers? That seems likely. I remove my own young birds as soon as the father begins to "chase" them from their perches. By then, they're eating okay and he wants them gone.
Past experience with Finches: I once had a beautiful pair of Zebra finches. The hen was all white and the male was pied. They produced gorgeous babies with a "saddle" of color over the backs of white birds. Very pretty. However, about the 3rd year the male began to throw newly-hatched babies out of the nest. I'd put them back, and he'd throw them out again. He continuously did this and wouldn't raise them any longer. They'd produce another clutch and he'd do the same thing. My belief is that he felt he'd produced enough progeny and only wanted to continuously mate, not work to raise young. I gave him away to a bird store.
Past experience with button quail: As a kid, I had a pair of cute button quail that hatched a large clutch. I
was shocked one day to go out to the aviary and find half the clutch bloodied and dead. Apparently, a male button quail will kill his sons after a certain age ... Sad. I don't know if every one of them does this, but enough do, that babies shouldn't be left with their dad for very long. Perhaps removing male button quail as soon as their eggs hatch is wise.
This sounds like it's the males of the species that savage their young. That might be typical, but I did have a female budgerigar parakeet who visited the nestboxes of other hens and killed their young. After she'd done this more than once, I finally caught her in a box that wasn't hers and realized who was doing it. She was "dispatched" and I never had another problem in that aviary.
There must be good birds and bad birds, just as there are good dogs and bad dogs, good people and bad people.