I have done this with my three dogs for years without incident. I don't adjust the food amount because the marrow doesn't amount to much of a meal. I don't wash the bones, and I throw them out when they start to wear...by that time all of the "meat" and marrow is off of the bones. It is dry and it looks like a plain old dog toy. Here are a few tips:

1. Get bones from some one reputable so they are as fresh as possible.

2. Freeze them when you get home.

3. When you give one to your pooch, do it in a place where they are confined. This makes the cleaning up process easier for you. Try giving them the bone in the kitchen, outside, or in their crate.

4. When the dog is finished, wash the crate/floor with a bleach cleaner, or some vinegar and hydrogen peroxide to kill off any bacteria that may make us humans sick. I only have to do this a couple of times, if that, because my dogs CLEAN the bones with pleasure. After they have had their bones for a day or so, they are a relatively clean.

5. Throw the bone out as they get smaller. You don't want Fido choking on a small piece of bone.

The subject of raw feeding and bones, etc, is a very misunderstood subject. It is making its way to the mainstream now though. Dogs and people have different digestive systems. I personally wouldn't eat a raw bone, but my dogs tell me that they are great....for four years strong.