I have 5 White Wyandotte hens that are apart of my flock of 19 chickens. They are a year and 5 months old. In the last few months we've only been getting 4-6 eggs a week compared to our normal dozen or two. These 5 started looking very dull, dirty even, and weren't as perky. No one seems sick at all. This past weekend I noticed new bright white feathers are coming in and some have bald patches right above their tails. Could this be molting?