Rotating a variety of hays and mixing multiple types (timothy, meadow, bluegrass, orchard, brome, oat, some alfalfa) encourage chins to eat more hay.
Many chins prefer pellets, they eat lots of (or all) pellets before turning to their hay. I think pellets are just tastier because of the molasses, wheat, etc... added and maybe some chins are just lazy (pellets are chewed quickly and easily).
I personally limit the amount of pellets and mix some herbs (rose hips, oat tops, chamomile, red clover blossoms) with hay for extra foraging fun! My chins got used to this diet, they actually prefer hay to pellets!
I used to buy regular grass hays, but want to switch to organic hays. I know some certified organic farms that grow organic timothy, brome, orchard. Their hay also contains small amounts of alfalfa, clover and some wild herbs (like dandelions), I think chins will be happy!
Carol~Anne, my chins also like fresh hay each day, spoiled fur balls!