Two queries:

I recently bought some meat from a butcher who told me he had greyhounds and that I shouldn't feed mine meat more than once a week (keeps them keen on chasing bunnies, he reckons). He said he feeds his dogs rice and vegetables and some kibble. I'm not interested in keeping my dogs 'keen'; quite the opposite.

Also, I read that feeding racing dogs bones only encourages bad behaviour between them. It's a worry when dogs come out of racing with bad teeth and, in the case of one of my dogs, gingevitis (and she had a good, kind trainer).