They just like to chew through haynet strings! We had a mum raise 6 cubs this year and they are so naughty now they are big! All sorts of things go missing, they like to steal my hoof brushes. They take any leather lying around. In fact the other morning I got up there to find one of my welly boots missing, I keep them ontop on my hay in the hay shed. Eventually found it in the middle of the fields ? thankfully not chewed though!