Hi everyone, if you don't mind I would like to give you my personal experience as my mother's little helper when she bred dogs (all big/giant breeds, we had Great Danes, Newfoundlands, Sharpei, Alsatians and Labradors + a couple Dalmatians).
What I remember clearly is: when they were fed on commercial diets, the effects on these dogs was hugely variable. Some dog food was awful (bad breath, lots of loose poo, ragged coats), others were ok, others were good (no bad breath, poo ok, coats ok). However, the best results ever were when my mum started going to the local chicken abattoir and used to buy carcasses (what is left once breast, wings and thighs are chopped off, still lots of meat on them), and also those wings/thighs that couldn't be sold because bruised/broken etc. My mum would take the lot home and mince it up fine, bones and all. Then freeze what was in excess.
Our dogs loved the chicken mince and ate it raw. Some of them might get a handful of cheap biscuits full in fibres if they were a bit constipated, otherwise nothing else. Poos were very small and well formed (even in the giant Danes!), glossy coats and lots of energy, but not mental.
However, many years have passed since and I have become a vet. I have seen many dogs brought in at the surgery because they ate bones, not just cooked but also raw. Bones can cause obstructions in the best of cases, and gut perforations in the worst. I have seen dogs dying whilst on the operating table trying to get the bones fragments out - too much intestinal damage. I have also seen dogs with bad lesions in their mouths because of eating/chewing bones. Cooked bones are the worst as they will splinter and break easily, but raw bones can do that too especially if caved bones like you find in birds. Rabbit bones can be as bad. Generally the big marrow ones are a bit better and less splintery, but I am still wary of them.
On the whole, I don't disagree with BARF diet, as long as it is not just meat. Wild dogs don't go for the muscled leg of deer, they go for the belly and herbivore's guts (with fibres in them). Only after they got that, they will start on the actual muscle and bones, and often leave it for days to "mature".
I think that if the meat is raw is fine, most dogs like the taste of it, but I would always mince it fine like my mum did. That way, the risk of bone pieces/splinters is much reduced and you still get the benefit of this diet.
Having said that, some dogs never really take to it, so as it's been said before it's trial and error for the individual dog.
Good luck, and try to avoid whole bones please!!