We have birds at home that we feed and raise; do they require zakat?

Zakat is obligatory on livestock (camels, cattle, and sheep) if they reach the [minimum] nisab and are pasturing. As for other animals, there is no zakat on them unless they are prepared for trade. If they are raised for trade, then zakat is obligatory on their value at the end of the year; otherwise, there is no zakat on them, because zakat is only obligatory on animals from the three aforementioned categories.