Jennasis, i hope the owner of the property gets in touch with you soon. granted, i'm not an attorney, just a former legal secretary, but he may be liable for the damage done to your shed, since the bullet came from his property. i would, in as friendly a manner as possible under the circumstances, let him know that i don't intend to put up with my property being damaged, my business being interrupted, my animals being scared and in danger, and my personal health being endangered. especially considering the size of the property, there's no reason, aside from pure laziness and spite, for these men to be so close to your property. it might be worth mentioning the possibility of his liability to him...this could solve your hunter problem, whether or not it turns out to be so. if i were the property owner (and i AM a property owner), i wouldn't want to take the chance i'd be held responsible for someone else's bonehead mistakes.
i hope today is the last time you ever see these morons.