First, welcome to the board, laughts and info within.
I don't feel you have a problem in the pen area other than it's proably packed down pretty good. Cow chips and other chips go into the compost piles, so why worry. How long have the dogs been gone?
You'll have to start at ground level, so to speak, and soften things up.
1] de-weed [pull and/or organic]
2] apply something like Medina Plus to start off the activity.
3] apply 1/2" of compost twice before next Spring.
4] add fine mulch to second application to retain moisture.
5] observe what others will post here. You won't be lead off the page.
6] post sign, "work in progress''