How to tell the sex of eggs and recently hatched chicks

Great e-Book!  Written in 1921, these techniques were used to determine the gender of chicken eggs before they were hatched using nothing more than a strong 'candling' light.  The benefit of knowing the gender of the eggs is you can sell the male eggs as food and only hatch the females, which can then be sold as mature, egg-laying hens.  It is wise to raise a few roosters for trading with other farmers to keep your flock's gene pool clean.