Size difference?

If you are handfeeding them the runt will catch up. If not the runt may die in the nestbox. Do you give the parents dry eggfood mix to eat? I give that to my parent birds when they are feeding babies. I buy CeeCee Dee or Higgins. You can also hard boil an egg and mash it up and give it to the parents to feed the chicks. If you are handfeeding then you don't need to do that. Handfeeding a bird from day one is alot of work. You have to know what you are doing or you will kill them. Plus they need to be fed every hour the first couple of days and then work up to every 4 hours. Using small amounts and if you give them to much you risk stretching out the crop and then they need help by a bra or have to go to the vet. Hope this helps.