feather picking can be due to boredom or need for protein. They are not crowded and have outdoor access, so I’d guess possible protein deficiency could be contributing. Layer feed has just enough protein, although some breeds do better with slightly higher protein. However, you are diluting the protein in the layer feed with scratch and veg. Mealworms have protein, but are also high in fat. Apparently too many mealworms frequently can cause fatty liver disease, but not sure what “too many” is per bird. Since feathers are protein, then they will eat feathers for the protein if they need it. Also, we’ve noticed that if a chicken is getting in pFeathers, that attracts the attention of some of the birds, and they will pick at the new feathers out of curiosity.
Laying around: typically happens more in hot weather. Their feed consumption goes down in hotter weather and goes up in colder weather. You can put out some frozen ice blocks in a pan or tray so they can drink the cool melted water and stand on/ in the ice if they want a cool down. Some people freeze water in recycled large soda containers so the chickens can lay next to them.