Yes, weed free hay
Most parks request weed free feed although when I camped there with my horse nobody checked. The ranger did come by and told my neighbor to keep her dog on a leash. They came by several times to check that she did but never asked about the hay with her either. Just to clarify, I did have weed free hay!
I don't have horses so I don't know but the rangers are easy to get ahold of just give them a call... Sorry
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