My sister has two black labs (13 and 1). I have a boxer-mix (7). All are female. All get along well. We often spend weekends together with all three dogs at either my house or my sister's house. We feed the dogs together and there is no squabbling. But...my dog often lifts her leg and marks one of the other dog's empty food dish after they've all eaten. Doesn't seem to matter which one and she has never marked them both. Doesn't happen every time. I assume this is some sort of dominance or territorial thing, and would like to head it off if I could figure out why she is doing it. She's done it at both houses, hers and theirs. No aggressive behavior, just a quick fly-by pee in the dish. Any ideas?
