Murphy is too skinny, how can I put weight on him in a healthy way?

[MayasMom]

Murphy was skinny when we got him from the pound at the end of October. He was an owner surrender b/c the guy lost his job, so I figured he hadn't been eating well. We took him to the vet and they did a worm check and a wellness exam, and said he seemed perfectly healthy. He hasn't gained any weight since then though. His ribs show and so do the tips of his hip bones if that makes sense. The vet said he thought he was a little under two years old when we got him, so he is probably right around two now.
He eats Eagle Pack Holistic Select Adult, four cups a day. We tried giving him an extra cup with each meal, but his stomach couldn't handle that much at once and he had horrendous gas. Our schedules don't allow us to give him an extra meal in the middle of the day. I'm not opposed to changing his food if there is something that may be better for him. Is there anything I can mix in that will be good for helping him gain weight?
I know how important it is for him not to be overweight, but I want him to be at a healthy weight. I read that boxers tend to fill out between 2 and 3 years old, but he just seems way to skinny to me. I've been back and forth to the vet with Maya for stomach issues, and I guess I may have to go back with Murphy so they can check him over again. My best friend's Great Dane has weight issues too, she tends to be underweight at times. She mentioned something called "satin balls". Does anyone know how to make these and are they a good way? (I can't get ahold of her right now to ask how she made them.)
Thanks in advance for any advice you guys can give me!

 

[Romy]

This is the recipe we use:

Satin Balls Half Recipe -- recommended amount to mix up

5 lbs cheap hamburger (for high fat %)
1/2 large box Total cereal (about 6 cups cereal)
1/2 large box uncooked oatmeal (about 7.5 cups oats)
5 raw eggs
1/2 of 15oz jar wheat germ (about 2 cups)
5 packages Knox unflavored gelatin
5/8 cup vegetable oil (this is pretty close to 2/3 cup)
5/8 cup unsulphered molasses
pinch of salt

The half recipe, using hamburger that is 20% fat calories, has 12,400 calories. The last batch I made ended up making 22 patties, so each has about 560 calories. I have big dogs (Danes) so if your dog is smaller you might want to make your Satin Balls or patties smaller.

I find that making the half recipe is so much easier that it is worth doing even though you have half-boxes of things around for awhile and have to mix it up twice as often. The disadvantage of the full recipe is the need of a really BIG container and it is very hard work to mix it all up.

Sometimes I leave out the gelatin if we are tight on money that month and it still comes out fine. We substitute Total cereal with something that has no sugar in it though. You can also boil/chop the eggs if you want, we like to vary it. Raw has more enzymes, cooking is supposed to make more of the lutein available.

If you dog has digestive issues, I would recommend looking into some digestive enzymes to start him on. This will also help him process the satin balls more easily too.

 

[RedyreRottweilers]

Nature's Farmacy makes one of the very best digestive enhancers out there.

http://www.naturesfarmacy.com

I would highly recommend you use these as well.