When two goods are in joint supply, an increase (a decrease) in the price of one good will lead to an increase (a demand) in the supply of the other.
Goods are jointly supply must be produced at the same time, although a producer may want to produce one of them only.
If demand increases for wool, sheep farmers would raise more animals for wool. There will be an increase in sheep meat production. This increased production will lead to greater meat supply and potentially lower prices.