Only feeding laying pellets
I would recommend that you continue to feed the birds a layer pellet year-round. That feed is going to contain the proper nutrition to keep those hens healthy and in egg production for longer periods of time. Scratch grains are high in energy and low in most other nutrients that a hen needs to maintain a healthy body weight and egg production. Think of it like eating a diet of candy all the time. It tastes great, but it doesn't keep you full for very long and it leads to over-eating and excess weight gain. In addition to that, scratch grains do not contain a supply of vitamins and minerals that are sufficient to support the needs of the animal. Your hens may act like they are starving, but it is for their own health and well-being that they remain on a layer feed.