as said before you can only catch rabbits that are in the burrows so dont be disheartened in small bags it will happen one day just keep at it mate. As for working ferrets on a line this used to be how it was done before the modern locators. A hob was used and was called a liner, a long line with knots tied in it at internals was attached to the ferret and he was then entered into the warren to find another ferret that had killed in, he would then kick the other ferret off the rabbit and stay with it until he was dug out. There was alot of work involved in this method as you had to dig a serie