Horses wont gain weight??

[Lehiy]

I've got two colts my friend sold to me, we loved their dam and after she passed we wanted to keep these two boys and train them up.

(Youngest, 2 years)
https://www.horseworldonline.net/horse/profile/2902786

(Oldest, 5/6 years)
https://www.horseworldonline.net/horse/profile/2901827

The older brother, Popcorn, I've had since he was probably a few months old. I tried training him after a while, but he wouldn't gain weight at all. He spent about 4 years in the pasture, on and off. Would very slowly gain weight in the pasture, but it'd take an incredibly long time. Then, as soon as I put him into the training barn he'd lose weight rapidly.

The same's been happening with his younger brother, Darien. They're on loads of feed in the barn, right now it's a mix of Hay, Sweet Feed, Performance Mix, and Weight Gain Mix. Most of my horses in the barn go onto 30% Hay and 75% Performance when they're 2 or so. With this, they all gain weight very slowly and stay moderately thin for a long time.

I've dealt with training foals and dealing with weight loss, but never anything like this. Costs $20 - $40 to feed them both a day, while it costs half to feed any of my other horses.

Really confused, hoping it's some sort of bug? I'd really like to be able to train them in a barn, it just makes things that tiny bit easier and I tend to forget if they aren't in the barn.

[BlackOak2]

I've got two colts my friend sold to me, we loved their dam and after she passed we wanted to keep these two boys and train them up.

(Youngest, 2 years)
https://www.horseworldonline.net/horse/profile/2902786

(Oldest, 5/6 years)
https://www.horseworldonline.net/horse/profile/2901827

The older brother, Popcorn, I've had since he was probably a few months old. I tried training him after a while, but he wouldn't gain weight at all. He spent about 4 years in the pasture, on and off. Would very slowly gain weight in the pasture, but it'd take an incredibly long time. Then, as soon as I put him into the training barn he'd lose weight rapidly.

The same's been happening with his younger brother, Darien. They're on loads of feed in the barn, right now it's a mix of Hay, Sweet Feed, Performance Mix, and Weight Gain Mix. Most of my horses in the barn go onto 30% Hay and 75% Performance when they're 2 or so. With this, they all gain weight very slowly and stay moderately thin for a long time.

I've dealt with training foals and dealing with weight loss, but never anything like this. Costs $20 - $40 to feed them both a day, while it costs half to feed any of my other horses.

Really confused, hoping it's some sort of bug? I'd really like to be able to train them in a barn, it just makes things that tiny bit easier and I tend to forget if they aren't in the barn.

You're simply ignoring the max feed the horses can eat, that's all.
You're trying to stuff more into their gullets than they can fit.

Take off all of that extra. Put them both on 100% weight gain and 5% performance and you'll see a vast difference. They might actually be able to eat as much as 100% weight gain and 25% performance. Skip the hay, the alfalfa, the cubes and the rest.

For in-depth understanding of what's going on, check out this link:
viewtopic.php?f=12&t=21892

Any additional questions or confusion, just let us know.