Let me tell you about this mare and see what you think. She's never been bred, she's three this year. She lost her coat like the big horses this year and didn't need to be clipped, which is a first. However, her hair is longer than our other minis'. She gets exercise, about 10 to 20 minutes almost every day. She eats but a handful of grain and is on dry lot with access to hay, but not free choice. She's 36" inches tall and she's fat! She has fat pockets on her sides, her neck is a little cresty and thick. However, she does not have a crease, and her spine is easily visible. I can feel her ribs through her padding, but she is still overweight for the amount of food she is getting. I definitely think she would remain the same weight even if I didn't give her any grain or hay - which I wouldn't do. So, I'm thinking the test is in order?