A rabbit circles its owner's feet because it is displaying mating behavior, it wants something that its owner is holding or it may want attention. The rabbit's urge to display mating behaviors towards its owner is caused by its maturing hormones.
Male rabbits often circle other rabbits when they mature or are about to mature at approximately 10 to 12 weeks of age, while female rabbits typically reach maturity four weeks later. If there are no other rabbits around, a rabbit will turn its attention to its human owner. This is the rabbit's way of telling its owner that it is attempting to court them. A rabbit that circles because of hormones will often spritz its owner with urine to mark them. This is used as a sign of ownership. Some rabbits may also follow their owner around very closely while making deep guttural, soft honking or oinking noises as an indication of mating behavior.
Getting the rabbit spayed or neutered often stops or minimizes the behavior. Circling that is caused by hormones may often be confused with general signs of affection. The typical signs of affection that rabbits display include licking and chin rubbing. During chin rubbing the rabbit rubs the scent glands located under its chin on its owner to mark them and display its ownership to other rabbits. The scent is undetectable to humans.