I have three black sex links for a backyard flock. They are all the same age, about 1.5 years old. Only one went through a true molt this winter, one has been laying an egg about every three days, and one, my previously best egg layer, has been dropping soft shelled eggs from the roost about two or three times a week all winter. Her egg has made it to the laying stage only two times in the last month. Our winters are not that cold, I am in Northern California. They all eat the same feed, organic layer crumbles, they have free choice crushed eggshells/oyster shell. They have plenty of room to roam in a large run area and have no predators that I am aware of. I don't know if she is sick or what, her comb is still red and she looks otherwise healthy. Any suggestions?