There was a thread on the Alpacanation website about alpaca feeders.  People were talking about feeders that did not rub the fur off of noses and kept the hay out of the fiber and off the ground.  My husband, Marty, built me a hay feeder that has met these requirements for our alpacas.  We did put a horse trough under it because initially the alpacas would lay under it and bump their backs and heads on the feeder.  They probably would have got used to it and worked it out, but I just wanted to insure their safety and an upside down horse trough was an easy solution.  It is mounted on a fence and the hay is loaded from the back. The roof has a hinge and it lifts up for easy hay loading access.  He built it about 3 years ago and it has held up nicely.  We should probably varnish the outside roof and sides to keep it longer.  The green rods are the plastic rods that gardeners tie their plants to.