I'm planning a flock of about 15 hens to house in a 8'X8'X7' H coop and 20'X8'X7' H run and originally was thinking I'd like to mix them up a little to get a couple of different qualities like prolific egg laying in a couple, maybe a couple of fryers, etc. But after reading more on the forum and in books I'm wondering if it's best for flock harmony to get all the same type of birds for the one quality you want the most, which in my case is a heat tolerant bird that lays a lot of eggs such as Barred Rocks or Red Sex Links. I definitely don't want to lose any birds due to injury and I also don't have time to babysit them for long periods. From what I'm reading I'm getting the impression that birds that look different or are smaller tend to get the short end of the stick in the pecking order, and sometimes you end up with injured or dead birds as a result. So now I'm thinking it's probably best to stick with one variety. I'd appreciate any opinions on whether this is the best way to go or if I'm over-thinking the issue which I tend to do a lot.