Hi kbs and welcome to the Forum.
Do you remember the date in January that they hatched - was it early or late in the month? This might make up to 4 weeks difference in their age now. Also, what breed are they? Hybrids often come into lay by about 20 - 24 weeks, but for many purebreds it can be much later, between 24 - 28+ weeks. If they hatched in January they are about 6 months old, perhaps, about normal for POL. If their combs are becoming red you may not have very long to wait. Have they started inspecting the nestboxes yet? Or do they crouch when you put a hand over their backs, because they are hoping for the attentions of a cockerel? These are other signs that lay won't be long coming.
Patience, patience! And do let us know more about them, and how they get on.