I have an order at our local co-op for eight Bovan Brown chickens. They are supposed to arrive on the 23rd of June. Since I placed that order I have found some other varieties of chickens that I would like. They are two days old today. I'd like to reduce my order of Browns to two and get six of the other ones in the next day or two. How would I go about combining these chicks that will be about 3 weeks apart in age? Thanks!