Julie,
yup, Chows soak up light. So do Newfies but there are some reflections with them at least. Not Chows. Keeshunds are another one but at least they're lighter in color.

Try using Noise Ninja on the Chroma channels to get out the artifacts from selective lightening of black Chows. You can fade it in Edit to get the effect you want while still keeping detail. Not sure about other noise-reduction software.

Personally, I didn't find the stable distracting at all. In fact, it added some dignity to the shot overall. I like that series.

As for Rescue, congrats and thanks for taking a chance with her. Rottie Rescue is, unfortunately, not as barren as Whippet Rescue and our kennnels and foster homes are always too full. I have a girl I'm looking to re-home that lives just a few miles from me and she's a total sweetheart. Fortunately, the family she's with will foster her until we find someone. I'll have photos of her later today. Too many decent dogs and not enough good homes.

Jim