Difference between hay and grass?

[Mikatelyn]

Hello!
I am at a store that sells supplies for farm animals, and they are selling bales of Timothy grass for significantly less money than when I get timothy hay at petco or walmart.
Is there a difference between timothy hay and timothy grass?
Is one safer somehow? Like is maybe one cured in such a way that it gets rid of potential mites or parasites and the other one not?
Thanks!

 

[Mikatelyn]

This is the stuff that they sell for horses I think. Is this ok for my piggies?

 

[Piggies&buns]

Not being able to see it makes it difficult but I’ve just done a quick online search and found the Standlee website and it looks to be a very green grass. I’m wondering from the website whether it is considered more of a forage (as in to be fed in small amounts) rather than the main part of the diet.
it’s possible that it is a readigrass kind of thing which is too rich to be fed in large amounts.
It’s not somefhing I’ve seen in this country though so I’m only going by their website

EDIT - I’ve just found a sentence which says it is not intended to be the only component of the diet and should be fed at a rate of 10% of the diet.

 

[Mikatelyn]

Good eyes!
Ok thanks!