At ten weeks, sickle feathers are still too short to be visible except for parting the tail feathers and looking at the emerging feathers. Usually a sickle feather will be noticeable as the only curved feather emerging from the straight ones.
If your photo is of a cockerel, it's too soon for slender saddle feathers to be visible, so looking for a sickle tail feather might give you the advanced notice you crave.
If your photo is of a cockerel, it's too soon for slender saddle feathers to be visible, so looking for a sickle tail feather might give you the advanced notice you crave.