Too skinny?

I agree with Peggysue in that he's getting entirely too much in the form of sugars/starch. My suggestion is to switch him to a complete pelleted feed at about 10 - 12% protein (depending on his exercise and energy level and work level - 10% is usually more than enough) with a higher fat content - around 8 - 10% is better than some feeds that average 5-6% for a horse that's a hard keeper. To help him hold weight you can add some stabilized rice bran pellets such as EquiJewel - as little as a cup a day can make a difference, or try muscle building supps that aren't just a weight building filler.

I've found that a lot of weight builders are just fillers with little nutritional quality. I've had great success with Fat Cat - which is a Vapco supplement that I get through EquiSupps.con (she donates to a horse rescue too and is cheaper than SmartPak!) and it's worked great b/c it has essential amino acids in it as well as several other ingredients that help healthy digestion and build muscle as oppsed to just being empty fillers to put on weight w/o quality. It was the ONLY thing - coupled with the high fat, moderate protein feed and the rice bran - that woud keep weight on my incredibly hard keeper TB eventer.

Good luck - he's a lovely horse and while not skinny, is a little on the lean side. This should help!

I don't see his ribs in any of the pics, and while his flank does look a little "tucked" some horses are more wasp waisted than others. If you can feel his ribs, but not see them, he's fine in the weight department. A bit more hay and his belly might look more round. I agree about the excess grain, but I don't think he needs to gain weight based off the pictures. Even seeing a little of the muscle that covers is the ribs is really not skinny, but I prefer a little flesh over them, but to still be able to feel them. He's fine, based off what I see, only I'd add more hay, less grain.

Thanks for all the suggestions y'all!! Since I buy my own grain, I'll wait until his sweet feed (Triple Crown Complete) runs out and then put him on a complete pelleted feed. Also I'll try Fat Cat, it sounds really nice. I'll give him a little rice bran too, but he doesn't like the taste and he's a very picky eater. That's why I was giving him sweet feed because he loves the way it tastes and actually eats it all. :P

Try some corn. That's what we did to get my horse at a better weight.

I'd be careful with corn as it generates heat as digested and can cause colic in horses due to the hard nature to digest. We've used it in the winter in small amounts to help horses generate heat on really cold days (in conjunction with lots and lots of hay).

Do NOT switch feeds. I and probably others though you meant "sweet" feed, which is what you stated but not what you are feeding. Yes, TC Complete is textured, but it is not a sweet feed. It is high fat, moderate protein and gets its fat from rice bran and pre-soaked beet pulp. It is not high in carbs and sugars, just average. It is an excellent feed.
Most horses do not like the rice bran pellets, so this is normal as it is quite bland (have you tried it?) Picky eaters eat around it and then you are throwing away a lot of $. You may want to try the FatCat as it has high protein, moderate fat, but contains probiotics so usually also helps weight and will help muscle. Or you can try Muscle-Up a muscle building supp from amino acids. Check out www.equisupps.com for the best prices and service and it also supports the rescue.
I would do less gallop work and more trotwork with lots of walking and trotting on the hills. If you lunge, smaller circles build topline, larger circles build butt. Good luck and post after pics.

Ooooh good catch on the TC Complete - I didn't see that and assumed a sweet feed - not the complete which is textured yes, but like she said above it's a GREAT feed - I've had my Clyde/TB on it who can be a bit of a picky eater.

Triple Crown COmplete is NOT a sweet feed it s a textured feed ... but you are prob over feeding it... get ride of the oats and substitute beet pulp or alfalaf pellets ... make sure you are not OVERFEEDING the TC complete it is an awesome feed

I was wondering because I've heard it referred to as a sweet feed before, I love it because my horse always has a lovely coat when its being fed. I actually worked hard trying to find the perfect balance and amount of feed, since I'm in Pony Club, I have tons of wonderful resources from the other members and the manuals (especially the upper level ones have tons of good feeding advice) and I have weighed all of his feed carefully. He is getting what's within the range of healthy for a 1500 lbs horse in moderate work, I was just worried that because he is a poor doer, he might need a lil something extra. I'm going to get the Fat Cat and the muscle builder, also I just started loungeing him regularly last week so I should start to see some improvement. When I bought him, he had no topline OR butt!!

Glad to hear that you've started longing him to build topline and proper muscling! That should help a ton!