Our native breeds of sheep in Britain are primitive short-tailed breeds like the Soay. They are small, hardy sheep that often naturally moult their fleece in spring and summer.
When the Romans invaded they brought with them big, long-wool breeds to help feed and clothe their legions.
By the Middle Ages these woolly breeds had been developed and wool became one of Britain's major exports, bringing in a huge amount of wealth. Many of the villages, churches and grand manors around where I live in the Cotswolds were built off the back of the wool trade.
Then, with the introduction of linoleum and polyester, sheep breeding concentrated more on meat production.
Our modern breeds are now very woolly and rotund in comparison to their forebears and they have lost the ability to moult.
As the weather warms up the sheep fleeces are fully grown, heavy, and very, very itchy. The sheep will rub and scratch and occasionally roll on to their backs.
Due to the weight of wool they become cast, unable to right themselves. Stuck in this position their rumen continues to produce gas that cannot escape, putting pressure on their lungs until they die.
If you ever see a sheep stuck on its back, do the farmer and sheep a huge favour and roll it back on to its feet again. You will have saved its life.