I've never heard of it being anything to do with kidney problems I would be surprised if that was the case.

It is a common problem, I would just try to ensure that you make sure the dog doesn't get the opportunity to eat it as habits are quickly formed.

My very well trained GSD did this on and off her entire life, YUK YUK YUK.
All I could really do is to make sure I cleaned it up before she did.

I have heard that it's much more common in bitches.

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