http://www.fwi.co.uk/livestock/dog-attack-leaves-11-sheep-dead.htm said:
The attack at East Lenham Farm, Maidstone, which left 11 pregnant pedigree purebred Romney ewes dead, is the third time the farm has suffered a sheep worrying attack this year.
Livestock farmer Alan Barr told how two dogs had chased about 50 pregnant ewes in a field last Sunday morning (8 December).
"I got there a bit late but the dogs had been there a long time. I found all the sheep huddled in a corner. Three of them had died there and then, while another had been bitten," he said.
"We called the police and found the owners. The next morning, I found a further seven sheep dead. They had all sat down in the evening and didn’t get up. They all had heart attacks.
"I called the vet over and as we were there another one keeled over in front of us and died."
Mr Barr believes the dogs must have been chasing the sheep around "for hours" as they displayed signs of stress and trauma.
The sheep that was bitten has so far managed to survive. However, he is concerned that more of the sheep could die in the coming days due to the stress.
So far, the attack has cost him in excess of £2,000, including the loss of the sheep, valued at £150 each, and the vet’s bill.
But Mr Barr fears the costs could escalate and he faces an anxious wait until mid-January when the surviving pregnant ewes will be scanned.
"If half of them have lost their lambs that will be a further blow," he added.
Two separate attacks, in March and September, resulted in the loss of about 40 animals, with costs of around £9,000.
"We have always had the odd attack, but to have three in a year is very concerning," said Mr Barr.
"Dog owners need to realise that there are pregnant ewes in the field at this time of year. If their dogs are not kept under control or on a lead, this kind of thing can happen.
"The public needs to be made aware that this type of incident can have serious consequences."
NFU south east environment and land use adviser John Archer said: "A handful of dog owners seem to think it is all right to allow dogs to run freely around farm animals.
"Even if dogs don’t physically attack livestock, chasing them can cause pregnant cows and sheep to abort or lead to panicked stock getting tangled up in fences."
A Kent Police spokesman said: "Police have spoken to the owner of the sheep and of the dogs and have recorded an incident of Worrying of Livestock. A community resolution has been agreed with all parties and it is understood that the owner of the two dogs – a German Shepard and a Jack Russell – will have the dogs destroyed.
"The owner of the dogs is considering compensating Mr Barr for his losses. The incident has been recorded as a crime, but provided both parties are happy with the conclusion there will not be any further action against the dog owner."
Rural insurers NFU Mutual has estimated the cost of sheep worrying is £1m per year to UK agriculture. But the true cost to the industry is believed to be much higher as many losses are uninsured and go unreported.
