Four of us walked a 16 acre calving pen that is entirely open except a small pond surrounded with trees looking for a calf born early in the day.
We circled the entire pen several times and I finally called a halt - - - I told them the mom was unconcerned so I was sure the calf was just hiding - - - next morning the calf was right next to mom.
I still have no clue where the calf was but it did a great job of hiding.