All three of my current birds were hand raised so I got them from a breeder. I highly recommend hand raised birds as being very healthy and also quite human-socialized.
Seeds are important, but remember they're only one small part of a balanced diet. Eating only seeds is like a human eating only white bread - the malnutrition will get to you pretty quickly. Be sure to provide a healthy mix of greens, veggies, fruits, bread, etc. to your keet!