As a side note: Often on sunny and/or windy days you'll have some dried and wet blood on a trail. What's in the sun or wind will dry faster than what's in the shade. That may be why you saw wet blood in the thicket, but dried blood after that.

Personally, I'd go to the last blood on the trail (dry, wet, or otherwise) and start grid searching. I've got the feeling that you're grind searching that thicket, which isn't where your last blood is really at.

Was any of the pink & bubbly blood a couple to three feet off the ground, like on saplings? If so, it's coming out the deer's nose, which is a dead give-a-way on a lung hit.

Best of luck.

JRW