Eighteen sheep have died after it is suspected that they were panicked into running on to a road by dogs.
The sheep, all ewes heavily in lamb, were being grazed in a field off the A269 just south of Boreham Bridge, Ninfield near Bexhill.
The sheep's owner was contacted by the owner of the land to advise him that one of his animals had been hit by a car.
Sussex Police officers arrived at the scene, near the entrance to Little Standard Hill Farm, where a badly damaged BMW had come to a halt.
The driver was unharmed, but reported to be 'very shaken'.
A total of 18 sheep lay dead on the road and into an adjoining ditch following the incident at 10.30pm on Sunday, February 12.
An examination the next day revealed the sheep had strayed some distance from their original field and that fencing had been stretched and broken.
A neighbouring property owner told officers that between 3 and 4pm, two people had been seen walking two dogs, thought to be brown Labradors, in the area.
However there are no public rights of way.
It is suspected the dogs may have spooked the sheep causing them to stampede and break their way out of the field.
A further 60 sheep had been affected, but had made their way back to the field, except for one that was found in a nearby slurry pit.
It is thought that some may well abort their lambs over the next few days.
Sergeant Tom Carter, of Sussex Police, said: "The incidents of sheep worrying by dogs show no sign of abating and it is worrying to note that Sussex now has more deaths than anywhere else in the country.
"The problem is widespread, however, and we are now part of a new National Police Chiefs’ Council (NPCC) working group linking with DEFRA to try and find solutions to the issue.
"In this case, there could have been far worse consequences for the driver of the BMW, who is not to blame for the incident, or for any other road users.
"With the first signs of Spring, more and more people will be getting out into the country to walk their dogs and we continue to urge them not to let them off their leads where there is or where there may be livestock.
"These sheep alone were worth more than £2,500 and their unborn lambs a further £1,350 - and that's assuming that each ewe was only carrying one lamb.
"Aside from the financial cost, there is the emotional impact on those who have raised and nurtured their stock.
"We urge people to keep their dogs on a lead while they are walking in rural areas and around livestock.
"So often in these incidents the owners are horrified by what their dogs have done, but they have to accept that even the most docile of pets can quickly turn into a killer given the opportunity.
"A farmer can legally shoot a dog that is chasing livestock and seek compensation from the person responsible for the animal, so please don't take the risk."
Anyone with information about the incident should contact Sussex Police using the online form
at sussex.police.uk/contact-us/response-to-appeal/ or call 101 quoting serial 1188 of February 12.