About 250 lambs had been born at Chyngton Farm in Seaford up to Monday after a busy few days.
Contract shepherd Ben Stead said on Monday in the past 36 hours 40 sheep had lambed.
He said about 600 lambs were expected from the beginning of February and another 400 in April.
“Everything has been fine so far,” he said.
“Some farms are suffering with the Schmallenberg disease but we haven’t had any of it this year.
“The sheep are doing quite well compared to the West Country, where it has been really bad.
“Early on this year there was a lack of grass and we had to take hay and silage out to them for a couple of months. They also came into the barn for a while.
“We’ve been quite lucky though. We haven’t had much snow and the sheep cope quite well in the snow.”
Ben said as a contract farmer he had been at Chyngton Farm since 6am and would then be going out to two other farms to help with their lambing.