Why

Cheese is best kept to the tiniest occasional nibble, because birds do not produce the enzyme lactase and so cannot properly digest the lactose in dairy. On top of that, most cheese is high in fat and salt, neither of which suits a 30g budgie. It is not outright toxic and a crumb now and then is unlikely to cause harm, but there is no real dietary need for it, so many owners simply choose to leave it off the menu altogether.

How to feed it

If you do offer it, choose a mild, low-salt cheese and give only a crumb-sized piece of the plain block. Avoid strong, mouldy, processed or flavoured cheeses entirely. Serve it fresh, do not add it to other foods, and take away anything uneaten quickly so it cannot spoil in a warm cage.

How much & how often

At most a crumb the size of a grain of rice, and only every week or two. Because dairy is hard for budgies to digest, less is genuinely better, and skipping it entirely is a perfectly good choice.