Very lovely!! Excellent light and detail, and a great pose – a perfect portrait composition. I think the BG color is just fine – it looks completely natural and the ewe stands out nicely. (Nature is often surprisingly good at providing nice color combinations.) Trying to tweak the BG color would be difficult to separate from the ewe and could easily give a cutout look.
My only (very minor) thought would be to soften the darker area in the LL corner.
I think the bg looks entirely natural and because it’s so smooth and evenly toned, it doesn’t compete with our beautiful girl at all. She looks darn healthy - the one time I was around them it was molting season and they all looked so raggedy. Nice sharpness throughout the face and horns. A tiny bit more room to the top and left might be interesting to see, but this works pretty darn well.
Wonderful portrait Sue and good job cropping to portrait. BG is perfect, showing her environment, which I always prefer. Nice turn of the head and great detail on the fur.