Wow! Lots of plans goings there! About fencing, plan for Godzilla, not Bambi. Goats can and will get out of most anything! Being intelligent animals, they love a puzzle! Electric is nearly a must, unless you plan on doing a lot of chasing. As for chickens and goats together, make sure 100%...
I am not an expert or anything, ,but it looks like it could be sore mouth. Very contagious. I'd contact the vet, just to be safe, especially since she's so close to kidding.