guttering. What is more, once it is set up there is no continuing energy need for pumping.
Where mains water is metered it will soon pay for itself in cash terms.
The thing that really makes the permaculture chicken house stand out is the fact that it
has a greenhouse attached to the south side. The body heat of the chickens keeps the tem-
perature up in the greenhouse at night, while the greenhouse helps to keep the chickens
warm on a cold winter's morning, and the carbon dioxide breathed out by the chickens may
enhance plant growth in the greenhouse.
An overall pattern emerges from looking at these two ways of keeping chickens:
work = any need not met by the system
pollution = any output not used by the system
The battery system is dependent on a continuous input of energy to fulfil every need. This
energy demand has been designed out of the permaculture system by making useful con-
nections between its different parts. In the battery house the heat, carbon dioxide and ma-
nure produced by the birds are pollutants, while in the permaculture system they are useful
It is only possible to use these outputs because of the diversity of the system. An 'edible
ecosystem', with chickens, greenhouse, vegetable garden, wheat field and orchard, can
have many useful connections made between these components. A monoculture of battery
This kind of diversity is only possible on a small scale . If hundreds of thousands of birds
are kept on a single farm there is no option but to feed them with bulk bought-in food, and
there is no way they can be let out into the garden or the orchard to do useful work.
Using the roof to collect water is an example of another permaculture principle. Al-
though a system may require some energy to set up, once it is running it should not need
any regular energy input from outside the system. In fact, once it is established, it should
produce more energy than it consumes . (Strictly speaking, it is impossible to produce
energy. We can only change it from one form to another. But to all practical purposes the
Sun's energy is unlimited and converting some of it to a usable form is a gain in real terms,
whereas using up fossil fuels is a loss. Rainfall, wind and the energy in living things all
come from the Sun.)
Using the body heat of the chickens, rather than paraffin or electricity to heat the green-
house, is making use of a biological resource . A biological resource is a plant or animal
that is used to fill a need that might otherwise be filled by fossil fuels or mined minerals.
The great advantage of them is that they obtain all their energy from the Sun. We, and our
descendants, can go on using them for ever, whatever happens to our stocks of oil, coal and