Never be fooled into thinking a fox would take or attack a Ouessant just because its small and sweet! I have 20 of them and they are the hardiest sheep I have come across! They will face up to my dogs, chase any phesants that come too close and are as tough as old boots!
Lambs of any breed are often at risk from foxes but personally I think that the larger breeds whose lambs tend to be a bit dim and slow at birth are at more risk than a Ouessant lamb which stands almost immediately after birth and is almost impossible to catch at 30mins old
You have to realise they are not the little sweet minature sheep they look but primitive tough proud sheep that are born survivors and think they are a lot bigger than they are
Mine are friendly and I really like them as a breed of sheep as they are very low maintenance... I have never ever had a lame one! Do beware of making rams over friendly though as I have now evidence of at least 3 really nasty Ouessant rams all of which have been made pets of because the owners thought they were sweet.
Dogs are always a problem with any sheep