I have read somewhere -on this site I belive- that the higher protien feeds ( in 20 - 27% like found in starter and gamebird feeds) may make your hens start early and lay smaller eggs for a while. This is exactly what happened to me. I would run out of layer and feed some chic feed or the game feed. My hens layed early (at least a month) and some pretty tiny eggs for about 2+ weeks instead of just a few days. But the eggs are bigger now and I don't see any other problems.