I'm a fairly newbie, had my hens for 18 months. I think what you're doing sounds fine, do you give them grit too?
I feed my hens decent layers pellets, which they have free access to, scratch mix or corn ( small handful in the afternoon) and some greens/apples/sweetcorn/peas as and when they are available.
Last winter I made a porridge with the pellets and warm water in the morning...with a few bits if sweetcorn and a few raisins...nothing fancy!
I'm not sure that filling hens full of "treats" is a good idea, I suppose I'm a bit old fashioned, but I've read on another forum the, in my opinion, junk food people feed their hens...leftover Chinese takeway? In my house the kids eat that anyway...:grin:
My girls like a good forage anyway, frogs and slugs.are favourites :|