My chickens always seemed to prefer laying mash.....the powder residue left over from the pellets seems to be wasted, as does the birds picking up a pellet and dropping it before they can consume it. With the mash, they consume what they have in their beaks and don't seem to drop it out. I have wire mesh over the feeders to prevent shoveling and flicking.
I mix whole grains of wheat, barley, oats, BOSS and a little cracked corn in my laying mash to provide texture and give the birds something they have to work at to digest. I like to believe it keeps their digestive tract healthier....imagine eating finely ground seeds that are compressed into a shape, all day every day. It would be easily dispersed in the gizzard as there is nothing really to grind....the gizzard barely has anything to do at this point. More easily digested, I'm sure, but no bulk fiber.
I don't provide as many whole grains in the summer months when forage is plentiful~ I feel they get their roughage well enough then.