White Bellied Caiques

I have 2 White bellied caiques. I feed them Kaytee Parrot food & sunflower seeds. They eat like crazy but still underweight. Any suggestion on what to feed my caiques so they can gain weight?

How much do they weigh? I don't think I've seen skinny caquies before as they are typicaly little pigs. Also what else do they eat? Fruits and veggies? Pasta? chicken? And have they been to a vet to rule out illness?

I have a vet appointment for them tomorrow. I recently started feeding them apples.
Im not sure how much they weigh. All I know if that when I pet and hold them I can feel there breast bone.
I never knew they can eat pasta & chicken.

Parrots can and should eat just about anything! Basicaly they can eat any thing EXCEPT:
avacodo
rubarb
uncooked eggplant
onions
uncooked potato
seeds from fruit
foods high in fat, salt or sugar
cocolate
caffine

Like everyone else said, give your caiques access to people food - they'll love you for it. Chicken bones = GREAT calcium for birds. Hard-boiled eggs with the shell on is great too. Just crush em a bit first so your bird gets the idea.

Stay away from rhubarb and chocolate (or any other candy).