I just adopted a Great Pyr from the Pound and he is underweight. I am considering the raw diet, but have heard that raw makes dogs aggressive. Is this true?

I'm just researching food for my great pyrenese. I just got him from the pound on Sunday and so far he's just the best pet ever. He's terribly underweight though--79lbs, so I'm trying to fatten him up. Never heard about alternative dog food before. How much would it cost to feed my great pyr this prepared all natural dog food? He's supposed to between 89 and 130lbs. Also, I've always heard that feeding dogs raw meat makes them more aggressive. Is that true? Our dog is our family pet and we have small children so I'm nervous about that. Would love to know what a natural diet costs. Right now I'm just giving him pedigree dog food and I've been adding eggs, wheat germ, flax seed meal and olive oil for extra calories. I tried giving him some carrots and apples, but he wasn't interested. Thank you for your suggestions and information. Also, are rawhide bones bad?

Andrea