You cannot buy chicken eggs in villages. They are exclusively for making more chickens.

The chicken eggs you buy at the market are battery produced by industrial 5 line cross birds.

What you  can buy are duck eggs and lots of them, usually laid by the Khaki Campbell or similar breed at the rate of nearly 300 per year. Naturally being such prolific layers, they normally do not sit on their own eggs, so you need an incubator if you do not want to be forever buying ducklings.Unlike chickens, ducks are mostly purebred so a lot easier in the breeding side of things.

If you have access to good wetlands, ducks will find a lot of their own food and will not attack your garden so viciously as chickens. Muscovy ducks are also very popular and a meaty bird.

Go down the market and buy 100 eggs, pop them in the incubator for 28 days and chances are you will get 90 babies.