Join Date: Feb 2012
Location: The land of Enchantment
If the hay you are feeding has little nutritional and caloric value, then there are a lot of options to supplement it with. I do not use sweet feed for a lot of reasons, it has way to much sugar and it is the first thing to go "buggy" on you (does not store as well). Oats store super well if properly contained, and are good when fed in small quantities in the winter or for a working horse. I prefer Nutrena Original Smart Choice, or one of the many feeds like it, to supplement hay with. There are excellent formulated feeds out there that do not have the unnecessary sugars but do have the nutrition.
I always weigh all of my horses food (hay, laken, nutrena, whatever..all of it), and I feed them 3x a day. It takes seconds per feeding to weigh, and leaves zero doubt "how much" they are getting and of what. You said what she was being fed, but not how much and how often. When you feed something as potent as sweet feed (or oats, corn, or cob, etc.,) its a good idea to measure.
Having a hay analysis done can be costly on an individual basis - it is far easier to ask the supplier for analysis. Some won't have one, some will. If your barn buys a lot of hay it has the leverage it needs to possibly bargain for "x,y" analysis.
There is just as much horse sense as ever, but the horses have most of it.