if the land owner agrees to you doing this, its not poaching, and to get rid of vermin he will most likely agree
i know theres a fair bit of lamping going on near me, nobody bothers
your issue may be that the dog now has a high prey drive which is being rewarded, so i would ensure the dog is leashed anywhere near any type of housing - it wont see much difference between a rabbit, a pet cat, or a small pet dog