Daddy Tiel Turning on Babies

Question
Hello, I've been breeding birds, finches, canaries and cockatiels, for a few years now. But I've never had nor heard of something happening like what my male cockatiel did, and neither has anyone else I've asked locally.

This particular pair, a female pied and a male grey, are about 3 years old. They bred for the first time last year with little success to begin with then great success once they figured out what they were supposed to do once the eggs were laid. They have their first clutch of the year now. The babies are just over a month old, getting their feathers and starting to look like tiels. About 2 days ago I noticed one of the babies had a couple scratches on it. Later the same day that one was worse and the other 3 had scratches on them. While watching the parents very closely over the next couple hours, I saw daddy bird eat and drink normally, then go to the next as if to feed them. I started hearing baby birdy screaming instead of the normal feeding sounds whenever daddy bird went into the nest. He wasn't feeding them, he was hurting them and not letting mommy bird get near the babies at all. I immediately separated daddy bird from the mom and babies in the hopes that mommy bird would still feed them. Unfortunately, mommy bird was chased away by daddy bird so much that even with him out of the picture, she wouldn't have anything to do with the babies. I've started handfeeding them as of last night, keeping them in their own little tank away from both parents. I put mommy and daddy bird back together once I removed the babies from the cage. Both mommy and daddy bird were very bummed to not be around each other.

Unfortunately the most injured baby did not make it. The other 3 seem to be doing fine but I'd like to make sure that they stay that way. I'm feeding the babies Kaytee exact formula every 4 hours or so during the day.

Any ideas on why daddy bird snapped? If you have any suggestions for the babies I'd like to hear them. Should I let mommy and daddy bird breed again and just watch them closely or would it be best just to separate them for good?

Sorry for the really long post and all the questions but I have no idea what caused him to do this.

Answer
Hi, Crystal.

Are these the only 2 birds in the breeding cage or are you colony breeding?  This sometimes happens when people colony breed their birds.  Also, if colony breeding, it might not be that particular bird doing the damage to the babies.

If you aren't colony breeding, it could be that the male isn't mature enough yet.  Could also be he perceives some type of danger to his offspring...sometimes birds will kill their babies versus allowing them to be injured/killed by something else.  Perhaps the babies are too much for daddy tiel.  If the birds are housed near a window, daddy might see something outside he perceives as a threat (birds don't understand glass in windows).  There could be many reasons...I'd need to really see what's going on or have more information in order to judge what the problem might be.  

This type behavior does occur.  Sometimes it only happens with 1 clutch of babies then all's fine; sometimes a bird does this with every clutch.  The only way you'll know if this will be a continual issue is to let them try again.  However, you'll need to be alert and pull the babies immediately when you see any type of aggressive behavior.  You did good by removing the babies for handfeeding as you have done.  I would remove the nesting box and give them a rest for a while and perhaps let daddy tiel mature a bit more.  Some birds just aren't breeding material, too.  Perhaps your male should remain a pet.

Chrys