The vet I work for specializes in avian medicine, an important thing for birds is to not feed them seeds as a primary food. Pellets are 100% better than a seed diet, there are multiple problems with seeds. The first being that sometimes they have little to nothing in them so it looks like your giving alot of food but some are just shells. Also it says they have "vitamins" on them, which they do, but birds dont eat the shells so they dont actually take in the vitamins. In addition adding vitamins to a birds water does them very little to no good as they hardly drink the water if you've ever noticed, it is not a suitable way to supplement the needed vitamins. If fed the proper pellet diet you do not have to supplement with vitamins. You can feed your bird a variety of table foods (I am sure there is a book with a list of yes and no's). Now dietary problems can take a long time to show (unless the bird starts laying eggs in which case deficiencies will show very quickly and may be lethal) but the important thing is to start the bird off right. If its a new bird to you from a pet store its probably relatively young so you should have no problem getting it to change from a seed to a pellet diet unless it was from a very knowledgeable breeder/pet store that has them on pellets already.