Ours only really show interest in timothy if they get it infrequently, otherwise they get bored of it very quickly. My lot absolutely love meadow hay, its full of different types of grasses and weeds so it seems to keep them interested for longer, they also seem to appreciate orchard grass. I find the meadow much cheaper too so waste becomes less of a problem, they'll always have favourite pieces though so usually the more stalkier bits will always be left.
Dont forget though, they eat their own poops, so a bit of pooped on hay is fine, I remove damp areas and refluff it back up each day and they go back to eating it just fine