Agree with this. Especially getting a EE or a buff Orpington, something like that. Australorps are great, but if you're selling chicks some folks will want variety also. An EE will give you pullets that will probably lay green eggs, and buff is one of the few colors that holds it's own against black, so you come out with gold and black birds.If you go by the 1:10 you would need 5 roosters. But you don't need 5 rooster because you won't be hatching eggs out of all 48 hens. First what's the goal of the hatchings? Fun crosses, meat, eggs? Identify 8-10 hens that satisfy your goals. Build a breeding pen for them and toss them in there with one rooster. I would select him based on how he treats the hens he lives with, his breeding, his chicks, ....If you control the breeding, you have a better chance of ending up with nicer, better put together, higher quality birds. Why propagate a hen that lays a tiny off colored egg? Isn't it better to promote the ones that lay 5-6 eggs a week over the ones that only produce 4-5 is eggs are the goal? 8-10 hens will give you 48+ eggs a week to hatch. Are you going to incubate the eggs or let the hens hatch them? One batch of 48 chicks should give you at least 30 viable chicks, count on 15 roosters for the freezer and 15 replacement hens. You might have all the chicks you need in a month with just one rooster and 10 hens.
I would probably go with 2 roosters. One BA and one "fun" rooster like an araucana or ameraucana and raise some EEs or whatever breed rooster is pleasing to you.. I wouldn't worry about them being raised together and would personally prefer roosters from different stock. If you want chicks May 1, you need to be setting eggs the first week of April. Give him 2-3 weeks with the hens before you start collecting eggs so that means he need to be ready to go into the pen with the hens middle of March. Minimum 2 week quarantine so that's the first of March when you need to have him.
I only see girls in your pictures.
Plus, having a breeding pen also means you have a grow out pen later. Once you've hatched what you want, disperse the breeder birds back to the main flock, now your breeding pen has a multitude of other uses!