Keep an eye on his crop and watch if he's emptying correctly, this is a good resource on handfeeding;
Less Is More Handfeeding & weaning Cockatiels
If this is your first time hand-feeding you may feel overwhelmed by what formula the feed, what type of utensil to are best to feed with, what you would put the babies in if you don’t have a...
www.ask-noodles.com
