Ruffed Grouse Questions from 2022.01.15

Ruffed Grouse were all around us in the forest when we arrived. Many were heard, some were seen, but even more so, their tracks littered the forest floor. There were these sunken oval impressions generally in the shape of a Grouse body pressed into the snow. We put our hands in despite the -20°C temperatures and felt the bottom the impressions. There was a hard icy crust in some of them, but not in others. There was scat in a couple, but not all. All had long chains of tracks emerging from them, but none had discernable tracks leading to them. What was going on?