I’m really against feeding purina feeds(senior especially, since it’s so high in sugar). But if you’re going to do a senior grain you can also look into Nutrena’s senior feed, it has beet pulp already in it. Or Triple crown senior(also has beet pulp in it, but has chunks, where nutrena is shredded and mixed in with the pellets) Both low in sugar, high calorie/protein for those older, hard keepers. I have all my horses on it and they do very well. I did a TON of research before I put my 18 year old on the triple crown, I’m super picky about what I put in my horses body.
you can get nutrena at most feed stores and the hay cubes/pellets almost every feed store carries them. Most carry Standlee hay company brand(very good, high quality feed).
I would have her teeth checked out. How long as she been doing this? Have you checked her mouth for sores? Maybe she got a bad flake with some weeds in it and hurt her mouth? Have you tried soaking her hay? See if she’ll eat it that way….
"Take the time it takes, so that it takes less time."
"Expect a lot, accept a little, reward often."