Not coon related but I have been buying some iegeek battery cameras that have a super bright LED light that you can set to come on when it senses motion. If your wifi signal reaches the barn you can monitor with it but even if it doesn't you could pull the SD card to review what it captures. The bright light might startle them and cause them to leave plus the recording will verify WHAT it is.
Here are the one's I have but they have a higher resolution version I aim to try out.
I set mine to record black and white at night so the LED doesn't' come on to spook anything. I have been amazed at how long the batteries last. The app interface leaves something to be desired but the motion detection accuracy is great. I have received far fewer false recordings that I did with other brands and they start recording pretty quick and capture what triggers the motion sensor.
EDIT: I just ordered one of the 5MP cameras to try. Same packaging but supposed to be higher resolution. I hope it has the same battery life.
hey do REQUIRE an SD card to work so you have to order that separate. I only use Samsum Pro Endurance cards these days. Too many failures on the SanDisk brand.