how long do you keep your chicks on starter feed?, sent my husband to get more chick feed today at the store and they said that they are finished carring it for the season....on one bag it said to feed layer's till 6 weeks of age and then switch to the next step of feed, the last bag of started feed we brought home it said to feed started feed untill 18 weeks of age.... at that age they start laying eggs so wouldn't it be unsafe to have them on it?....i'm so confussed.