Please be careful

My name is Kathy and I have a 9 week old cockatiel named Merlin.I have had birds in the past and they were on seed and fresh vegetables all were fine and healthy.While we waited for Merlin to be ready I did alot of reading on how seeds are bad pellets are good etc.Well Merlin gave us a scare and I thought we would lose him.He was eating the pellets,he loves roudybush crumbles,I know he was eating by his "poops".All of a sudden he stopped whistling and felt very boney when I held him.He was eating but not gaining.So after alot(and I mean alot)My husband brought up the fact that our other birds never had trouble with seed.He even said "you thought the pellet diet was so good".Now Merlin gets both pellets and seed and millet.The wonderful vet that I took him to said all birds need millet but beware pet stores do not want to sell it.They push the expensive bird pellets and tell you its enough.For some birds it may be but for Merlin he needs it all and now he gets it.Pellets are the best food for our feathered children but please be careful and make sure they are getting enough,don't let them starve like I almost did