I'm confused/anxious about B.A.R.F. vs. Raw Meaty Bones diet

hey--
so I'm thinking about getting a three year old rottweiler from the pound and cold-turkeying his diet from the crap he's been eating to a raw diet of some sort-- whether that's 70% raw meaty bones (of the raw meaty bone diet) or a mixture of fruits, veggies, meat, and bone for the Barf diet (I want to keep out grain unless there's a REALLY good reason to include it.)

Pros or cons for people out their feeding their dogs one thing or another? Any idea what's good for a larger dog (he's at least 120 pounds, probably more)?

also, I was in the store tonight sizing up the meat in the meat case (though not directly from the butcher as that section of the store closes up early.) there were beef back bones previously frozen for a really good price, which made me suspicious about how old it was. Granted, it wasn't VERY old, but you know what I mean-- I couldn't find a date on the package. As great as it would be cooked for a human, I want to get the freshest thing for my dog...mostly because I'm afraid of the alternative.

can anyone give me pointers on what does and does not matter about getting meat prepackaged out of the case? or, what matters and what does not matter re: how old the meat is? the free ebook "work wonders"
http://www.rawmeatybones.com/

said that dogs often like meat that might seem a little rancid to us-- because their enzymes don't work the same way ours do to break down our food (thus why we process grains better than they do, although that also has to do with length of intestine--ours, long. theirs, short.)
I was really impressed though-- for an upscale version of a chain grocery store (scholari's for those familiar with the chain) it had a wide variety of meats prepackaged: cornish game hen, rabbit, honeycomb tripe were some of the unexpected ones.

I'm also hesitant as I don't really know what I'm doing. the ebook talked about sharp edges on the bone, and I'm thinking-- well, the bone is cut, of course it's going to have a sharp edge.

I'm also really nervous about feeding a rottweiler chicken with the bone. beef bone is different, chicken bone is just so fragile! I don't want him eating a bone and then perforating something! criminy! I just hope he can survive til I get pet insurance for his perforated bowel <--- thus proving the chain of logic that disproves the old adage about people being less anxious/depressed with dogs.
the frozen cornish game hen because I can get the whole thing and just give it to him-- that's okay, right?

a couple of sources have recommended chicken as the first bone/meat after going cold turkey-- does anyone know why this is?