How do you potty train a puppy mill dog. She is four yrs. Old.

With tons of love and patience.

Start with the knowledge that dogs do not want to soil their sleeping space. Keep her in a gated or crated area and take her out a lot, on a regular schedule (dogs tell perfect time). Praise her profusely when she goes, and give her a treat once every 5 times or so, but randomly so she isn't expecting one, mainly just pats and praise. You can widen the gated area in the house as she learns. Close doors to any rooms you can if you let her run around the house. I still do that in bad weather when my dog doesn't want to go out.