Complex sentence: The Faroe pony has been on the Faroe Islands for many hundred years, in the 1960s there were approximately 5-6 horses left on the Faroe Islands because of the extensive exporting of horses from the Faroes for mining use in the United Kingdom.
Split into simpler sentences: The Faroe pony has been on the Faroe Islands for many hundreds of years. By the 1960s there were approximately five to six horses left on the Faroe Islands because of the extensive exporting of horses from the Faroes for use in mining in the United Kingdom.