Find my iPhone: my phone is moving on the map?

I forgot my phone at the barn the other day so this morning I enabled lost mode. As soon as I did, my phone started moving. Each time i refresh it, it moves farther away from the spot it was at (the sand ring), towards a field. I'm thinking some has it? But they would've had to cross a highway as well as a river and i believe the person would be on foot due to the fact that the app shows that my phone is on the middle of a field. I'm going there today so ill have a look around the barn and see if i can find it. I'm wondering if i should trust the app… Is it accurate? Does it actually mean that my phone is moving around or just a glitch? Thanks for the help!

Added (1). I checked again on find Iphone and now its on the street of my barn, much, much closer to the barn… This is confusing me really bad. I won't have Wi-Fi on my ipad over there so i can't track it once i get there so want to be able to make sure that it will stay in one place or if it doesn't, at least where it was but i just moves around almost at random locations around the barn each time i refresh it

My suggestion is to look for it where you remember having it last and if it isn't there then go back and try tracking it. My guess is it hasn't moved.

I would trust it. I also think you're right. Someone has picked it up but they haven't shut it off yet, so be very careful if you attempt to retrieve it. Don't get into a situation. Any way you could have someone monitor it for you while you go out there? Maybe borrow a phone from a friend so they can give you real time updates? Also, once you are there, have the person send the phone a message, and the 'I'm lost' sound alert so it possible you could hear it when you are nearby. Best luck.