My first booklet, entitled Don't Kill the Laying Hen, was made short and concise, so it might be easily understood. Many important points were intentionally omitted pending further investigations, as I did not want to advance any theories until I had carefully tried them out myself. After two years of almost constant observation of my own flock, and after collecting the specimens which are shown herein, I feel sure that poultry keepers will not only gain some new points from this book, but will also see reasons for many actions in their hens which they have noticed, and hence will be ready to accept what I have to offer. I do not pretend to give in this book a complete treatise on the care of fowls; but simply aim to give an account of my discoveries in regard to egg formation and development. There is yet much to learn about the hen, and I hope that every purchaser of this book will join me in studying how to eliminate the non-laying hen, which will most certainly increase our poultry profits.