Well it's good to know that I'm not the only one who has a girl marking. Thanks for the info about that. My little girl is spayed, so thankfully I don't have to worry about heat issues & unwanted pregnancies as well. Miss Momo is my first girl. So I'm still getting used to "girl behavior".
I'm actually extremely surprised that I was able to fix this problem without the use of a crate. In fact, it only took one week! That's why I'm thinking that the extra outdoor time had a lot to do it.
I have a new baby girl coming home next month. I'm def going to keep my eyes open for any type of territorial behavior (and anything else that may happen to come up). I have additional expens & crates ready...just in case.
Thanks again for the advice & suggestions