If the chins eat it and it's nice and green, it should be alright! Sorry, I was just playing devil's advocate for a minute there. Sometimes good hay can be hard to come by. Always ask where the hay comes from so you can get a good idea of how fresh the hay is and what animals or purpose it is intended for.
The hay that I get is directly from Nevada. I asked the hay broker where it was from and was able to get into contact with the people, who grew the hay to ask them if the hay was ever sprayed or if it was ever grown in fields with other types of hay. I've had some not so great experiences with hay over the years. I haven't gotten a bad bale that made anyone sick, but I have bought overpriced, dried out bales that the chinnies didn't even want to eat. The compressed bales were not a hit here, but in Arizona there aren't a lot of places that care about quality...they care more about quantity and price.
I'm glad that your chins like the hay you've found! I hope you can find someone to split it with...because that would save you an absolute fortune without any waste.