I use startfoder mixed with a seed mixture for parakeets and havregryn. 1/3 of each. I use this for the first two weeks and then gradually change the mixture till it's only the startfoder.
I have read that the seeds and havregryn prevents problems with diarrhea plus the havregryn contains the stof (wich I can't remember the name of) that is important for especially the larger breeds when growing.