I think there's two reasons: 1. They're partially insulating themselves from price changes in the chicken market. By raising the chickens themselves, they can

I think there's two reasons: 1. They're partially insulating themselves from price changes in the chicken market. By raising the chickens themselves, they can guarantee that they'll only pay a certain price for the chicken they raise. 2. Fewer intermediaries = lower prices since there's fewer companies that each need to make some money = higher profit