Complex sentence: The company keeps pregnant sows in gestation crates, where they spend most of their lives; the animals are given a week's rest after weaning, then impregnated through artificial insemination and returned to the crates.
Split into simpler sentences: The company keeps pregnant sows in gestation crates, where they spend most of their lives. They are given one week's rest after weaning, then impregnated through artificial insemination and returned to the crates.