Puppy Losing Weight on Homemade Food?

We were feeding our, now 10 month old, Golden, Diamond puppy formula labeled as Tractor Supply brand. He liked it, but it effected his behavior - made him psycho, running around like a maniac 15 minutes after he ate, and he scratched himself constantly. At night he chewed raw hot spots on his back end, and licked the hair off his forelegs and back paws till he broke the skin. His BMs were loose, he had control problems causing accidents in the house, and we saw blood in his stools from time to time.

I called the 800# and spoke with a Diamond rep. They said he was just being a puppy and was probably eating things he shouldn't that caused the blood in the stools. I searched the Inet for reviews and saw the high numbers of people that had the same symptoms, and some much worse with their dogs - such as hair actually coming out in chunks, and bloody stools every time, and as they all did, I took him off the food. He grew fast and gained weight on the dry food, but the negative effects were worrying.
BTW, that same company makes Costco brand, with exact same problems sited in their reviews.

I'm now cooking him chicken, we get a 10 pound bag of leg quarters at the grocery for $ .79 a pound. I boil it, pull out all the bones, add oatmeal, rice, and blendered (I know, I just made that word up, it doesn't exist) mixed veggies (because they just pass through whole if I don't). I make servings for him: 1/3 cup of clean, no skin, chicken, same amount of cooked brown rice, two heaped Tbsp. of oatmeal, and 1/3 cup of the soupy veggies and the same of the chicken broth. I'm feeding him the same volume 4 times a day that the dry dog food called for, with the added moisture. All the negative symptoms of the Diamond puppy formula are gone. He loves his new food, BMs are normal, he loves his walks and is much more obedient. He is not acting all hyper and totally out of control. There is no more excessive scratching and chewing with hot spots, and he now has hairy legs and paws again. I also noticed he doesn't drink as much water as he did on the dry food. He was constantly taking many long drinks before. We were constantly refilling his water, and he wanted out every half hour to empty his bladder - 24 hours a day!

All the negatives are gone, and he is a "normal" bright, attentive, active puppy. But, he has lost weight, and his hair doesn't have that glossy sheen anymore. He's not bony, just not filled out like he was on the dry food. I tried adding 1/4 cup of the dry food we still have half a bag of, because I thought there might be nutrients in it that he might need, but I'm not sure that's a good thing.

Am I doing something wrong, or do I just need to add some kind of additional nutrient to help him maintain his weight, or is his increased exercise of 2 or three walks plus play time with tug-o-war and fetch daily keeping him trim? He loves sweet potatoes and all kinds of fruit, especially bananas, but those things are not a part of his daily meals, instead they are more like treats. Should I give him maybe the same recipe with canned Alaskan salmon a couple times a week?

He's my fifth dog. I never had these kinds of symptoms with any of the others, and he is such a good, loving boy that also loves his new food. I just want to make sure I'm not hurting him in the end. He gets regular vet care, he's on a health plan through that Smart Place, and he gets his regular exams and treatment for heart worm prevention, etc. He was just under 80 pounds at nine months in the picture, a multiple person lap dog taking up more than half the couch, much bigger than the little guy he started out as. He is now down in the low 70s after a month on his new diet.
Advice will be appreciated.