I find there is a huge amount of variation from one batch to the next with hay.
This makes sense as depending on when it was cut, the quality will vary enormously.
Oddly enough I have had a couple of batches that didn't look particularly green and seemed a bit rough and the pigs loved it, and then sometimes when i think a hay is beautiful and soft they aren't so keen.
I find the best way to get good hay is to spend some time in the shop smelling it and seeing how it looks and feels.
Maybe that is why the kids don't like shopping at the pet shop with me anymore!