Are there any hens with lots of streaks, pencilling, almost all over them? Especially ones with salmon breasts? Or roosters with duckwings? Those are the best bet for crossing with silvers. If the silver bird is pure for Co, the chicks will grow up white with black tails but breed them again and there will be more pattern variety in the second generation..
If there are only black tail reds or black tail whites, no other pattern then it is about impossible to get other patterns out of these..
I have some kind of salmon or wheaten.. I don't know exactly. I will give you some pics of all chickens when I will be at my grandma's. She also has two chickens that are dark brown colored, like leghorns. And I would like to breed them with white columbian rooster. Is that combination going to give me some silver?