RIRs have a rep for being mean to other breeds, so maybe not a good mix with silkies, which tend to be very meek, I've read here. I don't have personal experience with these breeds myself though. I will give a hearty second vote for EEs, Easter Eggers. Great breed. Hardy and productive, laid-back, calm with other birds and people. Not subject to frostbite, good foragers. I also like Dominiques, they look a lot like Barred Plymouth Rocks but don't have the big single comb, so again, not subject to frostbite. Another calm, productive bird, brown eggs. Neither breed tends to be broody.