A feeder unit for pigs has an elongate trough with a hopper mounted over the trough for depositing feed downwardly and a feed dispensing control system at a bottom of the hopper so as to supply feed downwardly to make up feed taken by the pigs. The hopper includes four upstanding side walls forming an elongate rectangular open top edge with an open upper guide mouth located centrally above the top edge for locating a downspout of a feed supply system. The open top is covered by two inclined walls each extending upwardly from a long top edge of a respective one of the side walls and inwardly of the side wall of the hopper toward the open upper guide mouth and by two hinged dust covers extending from the short edges to the mouth.
