Complex sentence: The Finnish Landrace or Finnsheep is a breed of domestic sheep which has a high incidence of multiple births--it is common for a ewe to have three, four, or even five lambs at once.
Split into simpler sentences: The Finnish Landrace or Finnsheep is a breed of domestic sheep known for large lambing percentages. It is common for a ewe to have three, four, or even five lambs at once.