Jillian,
What I've done is watch the newspaper classifieds for offers of (usually) horse exhaust. I have a whole list of people with phone numbers so when I need some new exhaust for the garden I start dialing. Usually you can quickly identify sources for various "qualities" of compostables. For example I have sources for "barn litter" which includes a LOT of straw. Other sources provide the straight poop in the form of horse exhaust. Another source cleans out her barn once a year and sheep exhaust is available.
Another avenue to consider is rabbit breeders. There used to be a breeder near UC, Davis that grew large piles of bunny poo, but that was many years ago so now???? Try yellow pages for bunny breeders in your area. Also, check your local (nearest) fairgrounds. Most offer lots of horse exhaust + straw for the hauling. I have a BIG trailer and can haul many yards at a time. And for that matter, check into ARS (Animal Resource Services) at the UC, Davis campus...I have no idea what they do with all they produce. Their offices are located on the south side of the freeway and are not hard to find.
Actually, the classifieds have been a great source, just watch often and make a list. Works for me.
bearkiller
