I suspected it was hogs and got up to see both times. I used one of our heavy duty flashlights and crept out on our back porch. Sounds quite brave for me, but I was cautious and could tell by the sounds that they weren't close enough to the porch to get me.
Yes, it was a group of hogs, mostly smaller ones. The flashlight I was using had a narrow beam so I could only see a few at a time and they were running around in all directions. The first time I thought it could have been around 20 of them. The second time it was more like 10.
They were mostly foraging under the oak trees for acorns, I think.
A few mornings later, they must have been back because the ground under a couple trees was freshly turned over. The two trees are pretty close to the back of the house. Too close for hogs around the house.
(If you were wondering where Guv'nor was while all this was going on...he was in the Motherland visiting family.)