Our nearby non-GMO feed supplier offers a choice of 16% or 19% protein layer mix. I don't know which one to order. They call the 16% one their backyard poultry blend and market the 19% one as for "producers." Is 19% a better level of protein even for a backyard flock, or is it actually a bit too "rich" in protein? These will be my first chickens - right now they are still on chick starter at 13 weeks.