"Barnies" as I call them, develop later than other breeds. Depending on the source you got them from, it could be up to 9 months before they start laying.
But lots of the "rare" breeds like that tend to be only SEASONAL layers. They only want to lay in Spring and Summer. My sumatras are like that, so I only offer their chicks once a year. And I usually have an incubator set up JUST for them, so I don't fill the space up and have to wait for hatches before I can add their eggs.
So you may have to wait until the weather warms back up to get anything from them.