Oh dogs adore cat poop. Cats don't do a great job of digeting their food and the food we feed them is higher calorie than dog food its so the cat poop is full of lovely to dogs aromatic 'food'.
The danger is that she probably doesn't need the calories and could pick up parasites from the cats, if they happen to have any, and its icky as well as a bit germy when a poop eating dog comes and kisses you right after!
So the thing is how to keep the cats using a cat box that is out of reach of the dog.
You can try a circle of plastic needlepoint canvas (available from craft stores) or wire mesh (hardware stores) around your plants in the pots so the cats can't use the dirt as a litterbox. Or the plants can go up on a platform or from a hanger so the cats can't reach them (well some cats won't).
A top entry cat box is often a good choice for a home with a dog in it
http://www.amazon.com/Clevercat-Top-Entry-Litter-Box/dp/B0002ZS20I
Or a baby gate the cats can go over to use a private litter box with no dogs allowed!
But for dogs those are cat treats and recycling is normal.
Took my guys for a run today and they all found the horse manure before I saw it - its a dog thing and they all got a snack before I moved them along!
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