I never enjoy dispatching any chicken, meanest rooster or nicest hen. But I mainly raise them for meat so that is their fate here. Im also playing with genetics a bit, trying to develop a certain chicken. That requires a constant turnover until I get where I want to go. Ill admit some are easier than others. I had a cockerel this year, drop dead gorgeous and he acted exactly as a cockerel should, real good body shape, rapid maturity, plenty of attitude to make a good flock master yet his behaviors toward the hens and people were great. But his coloring and pattern was wrong. That one was a bit rough but you do what you have to.
My basic breeding flock is one rooster and eight hens. From when hatching season started and butchering season ended I peaked at 43 this year. I still have four to go to get there from a hen that went broody late.
I usually dont stick to it perfectly, stuff happens, but my system is to keep four pullets every year and overwinter the last years four. When they molt and stop laying, the older four go to the freezer. That way I normally have some pullets laying throughout their first winter and some older hens to maintain order, give me larger eggs, and pass on flock traditions. A rooster usually gets one or two breeding seasons before he is replaced, sometimes with a son or sometimes with an outside rooster to keep genetic diversity up.
I cant argue with what Bay said at all. What she said is dead accurate. Your goals are different than mine so your strategy should be different too.
There are a lot of different strategies for successful integration. To me the two most important parts are having plenty of room and housing them side by side so they get used to each other. My brooder is in the coop and I have a grow-out pen right next to the main run. Mine grow up with the adults yet are protected from them. I have lots of room. I normally integrate at 8 weeks but if space is tight, you might be better off waiting until they are practically grown. We all have unique circumstances.