What Is Organic?
Organic farmers use crop rotations to make the soil more fertile. For example, a farmer might graze sheep on a field one year, making the soil more fertile, then plant wheat the next and so on.
They can't grow genetically modified crops and can only use - as a last resort - seven of the hundreds of pesticides available to farmers (the Soil Association, however, only allow four of these).
Parasite problems in farm animals are controlled through regularly moving the animals to fresh pasture and other preventative methods, rather than routinely dosing the animals with drugs.