She is a pretty robust mare, isn't she?
I have a hard time looking at my own horses, too. I bought a weight tape and check them every two weeks to see where they are at and adjust accordingly. They look decent right now, but come June, my mares will look like tubs o lard! The pasture is divided so I can keep them off one side at a time so the grass can grow in before it's mowed down. This year, though, I am making a 50 x 75 sacrifice area to keep them completely off grass when needed.