The whitetail deer population is quite large around here. A few years ago, I was getting ready to bush-hog a neighbor's 4-acre pasture as a favor. It was overgrown with hip-high weeds, including Chinese pigweed. My wife was worried about fawns, so she and the neighbor actually walked the pasture together, about eight feet apart. Sure enough, they walked up on a fawn that was probably only a day or two old. The doe had tucked it in for safety while she went off to graze. It was able to get up and make its way to the perimeter, where it's mama joined up with it!
Walking a field first isn't realistic in most cases. About fifteen years ago, a friend's hired helper was mowing a pasture with a sickle mower when he noticed a struggling fawn. He'd cut off its leg on the previous pass. Our friend said the helper, a grizzled older gentleman who'd seen a lot in his day, came to the house with tears in his eyes, nearly inconsolable. He borrowed a gun to put the little thing down. I think of that every time I'm out mowing in tall grass.