Here's the deal: Silver is dominant over gold. So if you breed a silver male over a gold/red female, you get all silver offspring. Sex-linkage with silver and gold only works if you use a red/gold male with a silver female. I'm not sure about the genetics of a white leghorn, but they aren't necessarily silver. In this case, it could be, and probably is, as others suggested, one or both of the forms of white.
