Sussex laws on dogs at large. All rural counties have similar laws on at large dogs.
WHAT DO I DO ABOUT DOGS RUNNING AT LARGE?
First try talking to the owner of the dog(s). If the problem continues, contact Animal Control and report the problem. Dogs are prohibited from running at large without their county license tag and rabies vaccination tag fixed to a substantial collar secured around their neck. The Animal Control Officer is unable by law to take any action unless he witnesses the incident. Animal Control will attempt to resolve the situation using whatever legal remedies are available. Just because the officer cannot take immediate action, does not mean you cannot, you can make an application for the violation at the Magistrate’s Office.
As long as they have a license and rabies tag they're not at large. They go on to say more about hunting dogs. Note "foxes" in there. As I've said and I was told on the phone there is no violation as there is no law against chasing "foxes". As long as this loophole exists it's going to continue. When your lease is for all recreational activities you have the right to call and complain and have laws enforced. This land owner thing you've got going is just more BS that the dog chasers use to imply a solution exists when one doesn't.
Hunting Dogs & Hunters
Sussex County, as a rural community enjoys a rich sporting heritage, these traditions include the use of various breeds of dogs to hunt game, from birds to large mammals. The practice of “ pack hunting”, the use of a large number of dogs to drive game, is common throughout the county. Seasons for deer& rabbit span from November to February. Hunters may use dogs during seasons where not prohibited. Hours are from one-half hour before sunrise to one-half hour after sunset. When the chase begins on other lands, fox and coon hunters may follow their dogs on prohibited lands, and hunters of all other game may go on prohibited lands to retrieve their dogs, but may NOT carry Firearms on their persons or hunt any game while thereon. The use of vehicles to retrieve dogs on prohibited lands shall be allowed only with the permission of the landowner.
To answer this tract the pics are from is 500 acres. I've got dog issues on another that's 800. We had dogs on a 3,000 one before that ran during spring gobbler. I've seen that it doesn't matter how big they run on other's land if the deer they're on the trail of go there.