Crusty beak

[AdditveChick]

About 2 months ago, I noticed my chicken had molted twice and she seemed to struggle to grow her feathers back after the second one. I thought it was unusual, but we had just went from 90 degree weather, to 50 degree weather, back to 90 degree weather in the span of 8 days. She molted the second time before the temperature dropped. Today, when I was shooing them away from the cat food, I noticed her beak and comb had a whitish color. Upon further inspection, her beak is crusty on both sides. The inside of the mouth looks clear and healthy (despite smelling horrible, but I never smelled a chicken’s breath before). She’s still eating, drinking, and doing all normal behaviors. Just lost weight. None of the other chickens have this issue. Any ideas?
They’re free range. Stool normal. No pasty butt. Feathers are curled after molting.

 

[Eggcessive]

Can you look inside her beak for any yellow material on the tongue or inside the cheek or roof of beak, that may be canker (trichamoniasis) infection? That can smell rotten and grow in size to block the throat and spread to the esophagus, crop, and sinus. Take a picture if you find anything. I would try to clean the nostril with some warm saline or a drop of hydrogen peroxide, and QTips or a wooden toothpick to make sure the nostril is clear. Sometimes feed, mucus, and dirt can get stuck in the nostril and cause a blockage.