In case anyone is unaware the practice of mukesing is illegal in the UK, Europe, New Zealand and other countries too. UK & EU welfare standards are very strict.
Fly strike / maggots is a problem with sheep and is part of the reason for them being shorn. It can be controlled with chemical application which is preferable to an animal being eaten alive by maggots when it has hidden itself away to keep the flies off.
We don't have too much of a fly problem with our Easycare sheep because their fleece is always short but we still have to be vigilant in warm, wet conditions.