My Husband and I are new to having our own flock of chickens. Someone how we have ended up with 11 hens out of 12 purchased due to one death even with straight runs. Today we got a surprise and one of our Golden Comets started laying at 15 weeks. The egg was so fragile that it cracked before I could even pick it up. First question is that we have been feeding them the finish grower and have been giving them crushed oyster shells a few times a week. Should we go ahead and switch to layer feed now or wait until the 18 week mark? Second question is what is the ratio for feed per hen? We are finding some days there is a lot of food left but then other days there is nothing left and they act like they are starving. Third Question is we have a block of different types of bird seed that is like a cube we normally give them twice a month. Should we hold out the cube until the eggs harden up to make sure they are getting the right amount of calcium? Lastly, when we start up'ing the layer feed/crush oyster shells, how long before we should see a difference in the eggs. Thanks in Advance.