We found a black lab, 4 to 5 months old (we think), has white belly and some white on her paws. Just sitting in our front porch in the rain. She had a collar but no tag, and we took her to the vet to check for electronic tags, nope. We have a sign in our yard. Are we doing enough? we really like her and have been wanting a dog. is it wrong to keep her? how long before we stop looking for the owner?