I start the pullets on Layer when I get my first egg. I use medicated Starter/Grower. I feed it to the birds until I get my first egg then I switch over to Layer. If I have any Starter/Grower or Grower left over when I get my first egg, I mix in the leftover feed with the Layer feed. I have never had any problems. The amprollium in the starter helps in the chicks development in their resistance to cocci. It is sulfa based. There is only a problem eating the eggs layed by the birds that have had the medicated feed when they start to lay if you have any alergies to Sulfa.