source: Multiple births are common and work well in commercial operations, including programs where rams are specifically used to sire lambs for slaughter.
target: Multiple births are common.  They work well in commercial operations.  These include programs where rams are specifically used to sire lambs.  These lambs are sired for slaughter.
references: Multiple births are common.  They work well in commercial operations.  These include programs where rams are specifically used to sire lambs.  These lambs are sired for slaughter.