As far as I know, layers pellets and layers mash are the same thing just in a different form. A lot of people use layers pellets as it is less messy and wasteful. Layers mash tends to get spilled more and can be more wasteful. Your hens don't really need any more variety. They should have layers pellets or mash ad lib all day to get the proper diet for laying and as a treat maybe a small handful of mixed corn (can be bought from wherever you get your pellets from), in the late afternoon. Mine love the mixed corn and I sprinkle it around their run to make them find it. Occasionally mine get cooked peas, a small cold roast potato (mashed), green seedless grapes, cut into quarter, small bits of banana, apple bits with skin on. These are foods that mine get once every so often and in small quantities. Mine won't eat their veg cooked or raw
A liot of people feed their hens, vegetable peelings (except raw potato), fruit but not citrus fruit etc. Hope this helps. By the way, do not feed raw potato or potato peelings, it is poisonous to hens. If you go onto the omlet website there is a list of poisonous plants for chickens but that is more for things in the garden if they are free ranging. Mine are in a fixed run and I have 5 hens