My chicks are about 6 weeks away from beginning to lay. They are currently on starter/grower with a wheat grass fodder ration daily. I have about 3 weeks worth of starter/grower left right now. My question is should I go ahead and switch to layer feed when I run out of s/g (which will be 3-5 weeks prior to lay) or should I wait until they start. I don't really want to have a bunch left over and I don't know if it's OK to keep them on starter for the first few weeks of laying. Also, should I go ahead and start them on oyster shell now or wait until they start to lay?