A jubbly is a bird found during the Skrach Uglologwee subquest of the Recipe for Disaster quest. They appear to be a big, purplish version of a normal Chompy. They can be hunted and killed by using ogre bellows on an already bloated toad with a rock from one of the mineable rocks in the area and a ball of wool. Combining the wool and the toad creates a balloon toad which is used as bait.
After the subquest, they can be hunted as part of the Chompy Bird Hunting activity; each jubbly killed will count as one chompy in the player's kill count. Jubblies are not particularly hard to hunt. They do not actually attack players and only run a few squares away when they get too close to them. A good spot to hunt them is just to the east of the gnome glider, southeast of the Castle Wars arena, in the Feldip Hills. Once they are killed, they must be plucked to receive the drops. The feathers go into the player's inventory automatically, while the other drops appear on the ground.
Jubblies are also used in Creature Creation.