My BR hen Harriet stopped laying at about 15mos of age. This was my first flock so I was in panic mode when she started losing feathers in early summer and had not laid egg in 5wks. AT that time her comb was slightly pale compared to other hens. Vet took xray and blood work and diagnosed her with fatty liver. He mentioned causes such as nutrition, genetic, environmental, and or hormonal. I've read that higher egg producing hens appear the be the birds within a flock that are most affected and she was my first & best layer. His recommendation was to limit unhealthy snacks such as scratch and give her some tuna to perk her up and add vitamins to water. He added she could still live a healthy and happy life. She has not laid an egg since and is now 6.5 years old and tends to always go into molt early. I make sure she gets a high protein feed & diet and am very careful what added foods I give her. I add vitamins periodically or when she appears slower than normal. Please know I'm not suggesting your hen has fatty liver since many things can cause hen to stop laying with pale comb such as what you've already checked for, molting, vitamin deficiency, reproductive issues, diseases or environmental causes etc. Hope she feels better soon.