I believe she should be able to hold it for 4 hours, at her age, but if she can't, she can't. What we think they should be able to do is not really relevant.
I would use an x pen and a pee pad. I believe they can learn that when in the xpen they use the pad and when not in the go outside. but it is actually good to have them trained to a pad, so when they are left alone, they will use the pad rather than the floor.
Perhaps when you are home, remove the pad, so she has to go outside. |