Seven Baudet du Poitou donkeys were recently brought to Norley Farm, near Lymington, Hampshire, from France.
Owner Annie Pollock has started to cut up to 17 years of hair growth to stop the animals becoming irritated and overly hot.
She said: "It's not very nice being sweaty when you are this hairy."
Ms Pollock has kept Baudet du Poitou donkeys, which can grow up to 1.6m high at her New Forest farm for eight years.
There are believed to currently be about 75 of the animals in the UK, and only 950 in the world.