Shifting them to a high protein diet can cause them to start laying earlier, which may or may not be what you want. I followed Damerow's advice in the Storey's book and slowed the maturation of mine down with a mixture of whole oats and wheat. The purpose is to have their bodies physically mature enough to lay eggs. The theory behind this is that it will reduce the chances of egg-laying problems; like egg-binding, prolapse, and early cessation of egg laying. I don't know the results because mine are only nine months old but doing fine.
I had two first eggs with blood on them so two out of six isn't too bad, I guess. The first bird, an Australorpe started laying at 26 weeks and the last one, the Andalusian, started at around 34 weeks ( I stopped counting by then). All of mine are currently on Flock Raiser with oyster shell and grit available and doing just fine.
One of the concerns about early starting of layer is that the additional calcium may be hard on their kidneys. There was actually a thread not too long ago about a chicken owner who had necropsy results come back from a vet with internal damage due to excess calcium.
I like to let the girls regulate their own calcium. I have great shells.
Mary
