I have 3 buff orpingtons, 3 barred plymouth rock, 2 black australope, 3 silver laced wyandotes, and one bantam chicken. They are about 16.5 weeks old and I have just switched (today) to Purina Layena instead of Start & Grow. Is it too early to start changing their diet? I've looked at the charts on the other forum and read that it should be happening within the next 3 weeks for most of them. I've built nesting boxes and they have a great coop and are outside roaming for about 10 hrs. a day. Should I expect eggs soon? I live in Boone, N.C. so it's starting to have mornings of around 40 degree F. Thanks for the help!