I'm by far no expert in rabbit hunting but have been out a few hundred times in my life, never with a dog. The thick stuff is always great to push, but Id have to say ive had more luck on the smaller brush piles and downed trees with grass growing tall around them. With the thick stuff, I feel that they can sneak away on a face paced hop rather than bust out with there white tail flashing. When you hit the smaller stuff, they have no choice to bust out at full speed to get away. I have to say Ive pulled 80% of my bunnies out of stuff no bigger than a small car. Im sure there are a lot of bunnies in the big thick knarley stuff but they no they can sit tight and not worry. The smaller stuff they have no choice because they know that they'll be seen. Id concentrate on the smaller downed trees, brush piled and thick patches of grass. If you give them enough of a kick and work slow, if there are bunnies in there they'll eventually get out of there at full speed. Id stick to the thick big stuff when you run out of the smalller stuff. Again, this is my 2 cents and I am by far no expert but have done a lot of bunny hunting in my day. Good Luck!