Ogre bellows are obtained by "unlocking" a chest locked with an ogre lock (i.e. pushing a boulder off from on top of it) in the north-west part of the cave (not on worldmap) in eastern Feldip Hills where the ogre Rantz and his son and daughter live, directly north from the quest start icon where Big Chompy Bird Hunting is started (fairy ring code AKS is nearby). Normally only one can be in the player's inventory, but it possible to use the drop trick to obtain multiple. Note that if you have an ogre bellows in your bank, you have to take it with you to obtain more copies.
This item is also needed for a section of the quest Recipe for Disaster and Mourning's End Part I and the western provinces diary.
The bellows are first filled with 3 loads of swamp gas from the swamp to the west. They are then used on the swamp toads found nearby to produce bloated toads. Only three toads may be carried at any one time in your inventory, though more than three may be laid on the ground. The now incapacitated bloated toad may be placed anywhere in the ogre area to attempt to attract a Chompy bird.