Unfortunately a very average and cheap set of bolt cutters will go through about 90% of most chains and padlocks.
Any going about this sort of thing are likely to have something if for no other reason than to deal with the farm gate!
My wife recently got 1 of these for the dog and it’s actually very impressive. Well at least she says it’s for the dog but I’m regularly sweeping my car!
https://tractive.com/en/pd/gps-tracker-dog-xlIt’s £4.50 a month subscription.
You are able to set a safe zone as well on a very detailed sat photo so you’ll only receive pings if dog/hive moves outside that area. You simply draw a line around garden/apiary on the map. This also increases battery life.
Literally as soon as the dog goes outside any safe area your phone pings giving a sat picture of exact location and it’s updated in seconds.
The actual tracker is about 60mm long about 30mm wide…25mm thick. Probably very easy to hide in floor roof or bottom rail of a box.
Probably worth looking at for any that expect to have issues or try on the pet first or of course the other half