the silvers are a natural occurence out of certain strains of cuckoos. I believe, a lot of this is just things I've heard people say, but are the silver counterpart to a golden cuckoo. In the UK silvers were once pretty common, but fell out of favor and all but disappeared, believed to be extinct, but that gentleman I've been talking to and his wife got some cuckoos to go with some of theirs in the 70s and ended up with the silvers. So, I'll be interacting a lot with them regarding what they have learned and what they have had success with and etc. Should be interesting and a learning experience for sure.Vicki~ Congrats on the chicks! What a nice surprise! If you don't mind me asking....what gives them the spottie and chipmunky looks? What Marans varieties are in them again to make them the Silvers?