I am seeing a lot of bad posts about Medicated chick feed. My chicks are 4 weeks old and I have feed them Medicated chick starter everyday sense they were 1 day old. When is a good time to take them off of the Medicated starter and go to NON medicated starter or layer/grower feed ??? Will this hurt the chicks to keep them on medicated until they are old enough for layer feed ?? Thanks for any good advice.