An IB hen may lay a few eggs at two years of age, they are kind of hit and miss as to being fertile. They are not very good at the mechanics the first breeding year. At three years of age IB's will start production and will lay around 25 and maybe more the next year. Greens on the other hand are about a year later than IB's. A two year cock if he has a few eyes will be mature enough to breed but we never put more than two hens with a young guy like that.
