I would recommend a Black Australorp for breeding with them. BAs are very hardy. I've raised them both in CA where summer temperatures frequently reached 117-118 F (123 F once) and in northern Kansas, where the temperature dropped to 30 F below zero one winter, and in both areas they came through unscathed. They are also very calm and gentle, which is a good trait to breed into your offspring, and they are the best layers of the standard, brown egg laying breeds. Until it was broken by a caged White Leghorn in 1879, a Black Australorp held the world laying record with 364 eggs in 365 days, and while mine have never reached that kind of production (and likely never will), I've had a few of them lay over 300 eggs in a year. By using a BA rooster, you would be infusing all of these good traits into your offspring. Whatever kind of rooster you end up getting, good luck with your hatches.