I'm a little bit - well, A LOT - obsessive about hay. Hay makes up most of P and AP's diet. I try to calculate as best I can, but I always worry about having enough to get through the winter. So much depends on bale size and quality every year. But I think it's really important for horses to have enough hay, and in P's case, she needs very soft hay that she can chew.
I buy local hay and have had a very basic forage analysis done in the past. I didn't get a full vitamin and mineral report, but I did get things like protein, fat, digestible energy, and few of the major minerals. The hay usually comes from a lot of different fields, so it doesn't make sense to test all the time, but it does give me an idea of what I'm feeding and what the hay is like in this area.
I've had some wonderful hay, and I've also had some moldy bales and weedy bales. I try to check each bale very carefully before feeding.
Hay making is hard! I'm really grateful for the farmers who watch the weather reports carefully and who are out there working hard on hot summer days to make hay. Our weather patterns haven't made it easy the past few years, and the hay crops haven't been great. I hope there's enough good quality hay this winter.