Silkies are not a Table Bird which means each bird does things at it's own maturity rate similar to people -
a year is not uncommon and doesn't mean you are doing something wrong -If it is a Buff I have heard of Buff Silkies laying only 6 to 8 eggs a year - The Buff Genetics mess things up. The higher Quality the more issues they have being Breeder Quality -- Everything in Silkies is a trade off --