They're all different when it comes to molting... some take a few weeks, some longer. I'm sorry we can't tell you more, hens are just funny that way. If their feathers look rough and they're losing them etc, then you can try boosting the protein in their feed, either by getting some flock raiser or adding some meat scraps, fish scraps, or maybe some dry cat food (not too much of the cat food) for a few weeks. That gives them more energy for feather growing. Make sure they have plenty oyster shell for calcium esp if you go with the flock raiser... it doesn't have calcium like layer mash.