Farmers inside the bluetongue control zone in south-east England have said they are being forced to sell sheep at half price because of restrictions.
Farmers are making sheep sale losses in the main bluetongue zone
The animals can only be moved within the zone stretching from Norfolk to Kent and Sussex - except for slaughter - limiting where they can be sold.
East Sussex farmer Frank Langrish said he was down thousands of pounds on last year at Ashford's livestock market.
And he warned that those buying sheep were being "brave speculators".
Sheep and lambs would normally have been moved onto the South West for fattening at this time of year, as farmers in Kent and Sussex run out of feed for them.
But they cannot go beyond the control zone boundary in Sussex.
Mr Langrish - who recently had bluetongue confirmed in some sheep at his farm in Northiam, near Rye - attended the Ashford market on Friday.
He said: "There's so few buyers here, they can only come from the control zone which is basically Kent, East Sussex, Essex, Suffolk and Norfolk.
"But there's very little grazing there and these people are being quite brave speculators in taking them anyway."
Howard Bates, from the National Farmers' Union, said that with feed running out there was simply no choice but to sell the sheep on at a reduced price.
"No good farmer will ever allow his sheep to starve and he will make a serious decision about disposing of them through the market at a great financial loss, on welfare terms," he said.
"Time is running out and with a change in the weather it'll be too late."
The only way ruminant animals can be moved out of the bluetongue control zone is for slaughter purposes within the much wider protection zone.
Defra said it had to "weigh up the needs of people in the zones being able to move their animals, with the risk of spreading disease further".
It added that it was "not the government's position to pay compensation for wider consequential losses from any disease outbreak".