Sustainable Kashi, here at Kashi Ashram has quite a few projects going on which are aimed toward growing and producing their own food. One of these projects is their stand-alone, off-grid solar goat house.
Goats are one of the various animals which can be integrated into a successful permaculture system. Goats can consume most any bio-mass and turn it into compost and/or milk, but like any other design option, a cost/benefit analysis should be done to determine if goats are the best option for your design. Some of the things to keep in mind are that goats are escape artists, and can be absolute terrors of left free-range in a garden or forest, eating all least greens and even chewing the bark off of trees. The flip side of these facts though, is that they can make excellent land clearers, as long as you are aware of their needs.
Kashi decided to integrate them into their system using solar electric fences, water catchment, and a milking parlor. Check out the walk-through: