Well, I am a member of the Nebraska Alfalfa Marketing Association, so I have to mention the www.nebraska-alfalfa.com website.  there is inventory listings and names of grower members.  That said, I haven't listed my inventory for many years on the web even though i have hay.  between hay brokers and telemarketers, the phone rings and i would never get anything done.   
    the best time to check the inventory lists is the start of the world dairy expo next week or later.  Im going to be in the field for the next week putting up the last (and hopefully highest testing) cutting before i concentrate on selling it.

next, have you seen the weekly wednesday night hay auction on dvauction?   https://americanagva.dvauction.com/ satellite or web, Tom usually has several hundreds of tons available weekly.  he visits farms and videotapes the haystacks just like a calf sale on the ranch.   I sold a load through him several years ago and didnt like the commission taken out, otherwise it serves a purpose.  https://americanagva.dvauction.com/events/178705/lots

Im in Kearney, Ne and will have some 4x4x8s for sale 150-250rfv in the barns ill be listing in a couple weeks but i dont want to abuse the forums here.