The Polyface Farm Model
Sadly Permaculture is sorely lacking in the widespread/effective implementation of animal agriculture systems into the landscape. Luckily other examples exist. The most prominent such example would be that of Polyface Farm, owned by Joel Salatin. Mr. Salatin manages his ranch in such a way that promotes ecosystem health and biodiversity, and nets him a "white collar" salary.
Beef is the keystone enterprise in his operation. Using electric fencing he manages it such that, in the summer months, the cattle get no more acreage than what they can graze evenly in a day. The next day they are moved to an adjacent paddock, and so on. Doing this shocks the grass without depleting it, and more closely mimics nature's example. The result has been enormous. Mr. Salatin reports that he is building soil, and that he has effectively doubled the carrying capacity of his farm. In his book, "$alad Bar Beef" he writes that he has effectively purchased another ranch for the cost of good management.
Another of Joel Salatin's pioneering examples is that of his Egg Mobile. An egg mobile is a chicken coop on wheels. Every couple of years he stocks this device with 200 young birds, and with his tractor pulls it to the paddock that his beeves have just grazed. The chickens excitedly dig through the manure patties searching for larvae. This action spreads the manure AND deworms his fields. Two chores that most farmers pay to do. By doing this his hens are able to forage most of their food, dramatically cutting back on his feed costs, and the eggs, which he sells locally, are said to be "the world's best."
Most farmer's work hard to keep their barns clean, often at an expense. Not Joel Salatin. Like many ranchers, Mr. Salatin adds carbon-rich bedding material to his barn floor throughout the winter. What he does differently is add corn kernels into the mix as well. As the bedding is turned by the hooves of cattle and the bedding is added on, the corn kernels ferment and become slightly alcoholic. In the spring Salatin turns his hogs loose on the barn. They eagerly root through the manure/bedding mix in search of the corn, which has become a special treat for them. This has the effect of turning the mixture and resulting in a compost that is then spread on the pasture.