The picture of your horse, wet is fantastic and the coat is slicked and not hiding anything.
So, nice horse, but she is thin.
She needs a solid hundred pounds on her frame and I am one who does not like to see horses fat.
In your mare though her markers are showing...
Shoulder point, tailhead to prominent, pointed rump, her rump top not softly rounded but angular, her SI {pelvic} joint is not well covered ....her wither is prominent with no surrounding fat pad and her shoulder joining her neck is, well, she is underweight.
She has little muscle-tone either, like none.
She is rather a steep croup and straight hind legs, but...she should still have more meat on her bones covering that joint.
So, her hay is not enough for her... She needs fed about 2% of her full weight daily in hay eaten. A 1000 pound horse needs 20 pounds of hay minimum and she guessing she is about 16 hands, maybe more needs 20 - 26 pounds truthfully. {half a average bale of hay for her to eat all by herself!}. Fully fleshed & weighted she is going to be between 1,200 - 1,300 pounds..
You can not count on pasture to feed the horse but to occupy the horse unless the horse is out to graze 20 out of 24 hours every day.
So, double the amount of hay she is fed, and feed according to a bags directions for a horse in moderate work since she needs to gain.
Horses are fed by weight, not volume....
Her senior feed is about 4 pounds worth if you use a normal sized scoop not the 4 quart size which is large in appearance.
She appears really healthy just needs more calories to eat.
You need to feed in more that the horse burns just being a horse and every move she makes, activity he does with you burns her energy stores which are fat off her frame.
15,000 calories a day to survive.
23,000 to gain...
33,000 for one recovering from emaciation or serious illness is a rule of thumb.
A chart about foods and how many calories per pound is below and another about hay...
Now weigh your foods fed and the do some math and see where you are...
My gut is...
Double her hay fed.
Feed her 2 heaping scoops of senior feed...
I guarantee you she will gain if you feed her enough.
The last weight put on a horse is the hardest to get and keep on the frame...it will come, just give it time.
Take pictures same place, same stance, same time of day for shadows on the body and also do tape measurements so you will see the improvements our mind tricks us to not see when we see often....measurements and pictures don't lie.
She is no longer racing fit, so indeed thinner than what you want.
🐴....
So, nice horse, but she is thin.
She needs a solid hundred pounds on her frame and I am one who does not like to see horses fat.
In your mare though her markers are showing...
Shoulder point, tailhead to prominent, pointed rump, her rump top not softly rounded but angular, her SI {pelvic} joint is not well covered ....her wither is prominent with no surrounding fat pad and her shoulder joining her neck is, well, she is underweight.
She has little muscle-tone either, like none.
She is rather a steep croup and straight hind legs, but...she should still have more meat on her bones covering that joint.
So, her hay is not enough for her... She needs fed about 2% of her full weight daily in hay eaten. A 1000 pound horse needs 20 pounds of hay minimum and she guessing she is about 16 hands, maybe more needs 20 - 26 pounds truthfully. {half a average bale of hay for her to eat all by herself!}. Fully fleshed & weighted she is going to be between 1,200 - 1,300 pounds..
You can not count on pasture to feed the horse but to occupy the horse unless the horse is out to graze 20 out of 24 hours every day.
So, double the amount of hay she is fed, and feed according to a bags directions for a horse in moderate work since she needs to gain.
Horses are fed by weight, not volume....
Her senior feed is about 4 pounds worth if you use a normal sized scoop not the 4 quart size which is large in appearance.
She appears really healthy just needs more calories to eat.
You need to feed in more that the horse burns just being a horse and every move she makes, activity he does with you burns her energy stores which are fat off her frame.
15,000 calories a day to survive.
23,000 to gain...
33,000 for one recovering from emaciation or serious illness is a rule of thumb.
A chart about foods and how many calories per pound is below and another about hay...

All Flakes of Hay are Not Created Equal
I was called out to farm to review a horse that had started to lose weight. The owner explained to me that the horse had been diagnosed with ulcers, so her v
www.horsefeedblog.com
My gut is...
Double her hay fed.
Feed her 2 heaping scoops of senior feed...
I guarantee you she will gain if you feed her enough.
The last weight put on a horse is the hardest to get and keep on the frame...it will come, just give it time.
Take pictures same place, same stance, same time of day for shadows on the body and also do tape measurements so you will see the improvements our mind tricks us to not see when we see often....measurements and pictures don't lie.
She is no longer racing fit, so indeed thinner than what you want.
🐴....