It is hard to summarize the whole thing together because there were many subtle things going on, but one thing was how they acted differently when they noticed

It is hard to summarize the whole thing together because there were many subtle things going on, but one thing was how they acted differently when they noticed humans were not around. E.g. escaping barb-wire fences that looked like they would hold them to get that good gras next to the hut only to vanish back behind the fence when the sound of the farmers car was heard. They knew what was allowed and what was not allowed.