If you really don't like the dogs and you want their owner to keep a better eye on them and you don't want to kill them, you should just put some live catch traps out for them, and then split the paws on their feet so they can't run, and drop them off at the pound. When it costs him money to bail them out and costs him money to get them healed up he will be more watchful. Also, if they look like real good dogs, cut the balls off of every one of them. He will probably be looking to get rid of them then and you will be in the clear!