I have 6 red sex link hens ( Rhode Island Red/ Rhode Island White cross) that are 8 months old. What breed will be compatible with mine if I can't find the same that I have now. I am looking to add 4-6 more. When I do, should they be seperated, and if so for how long. My girls have been laying constantly for about 3 months. Will the new additions disrupt their laying eggs?