Post photos--at 14 weeks it should be getting easier to pick out the cockerels.
For Easter Eggers (what I'm more familiar with), look for bright patches on the wings/shoulders (or sometimes solid patches). Depending on the color of the bird, dark breasts will sometimes point out cockerels. Cockerels should also start getting some pointy hackle and saddle feathers by this age.
ETA: for Amaruacanas it will probably greatly depend on the specific colors. But I would think the combs and pointy feathers should start to be obvious indicators soon.