The Kadoatery is located in the Neopian Plaza.
This is where Kadoatie owners would leave their petpets while on their vacation. To please these pretty kitties, one must feed them an item of their choice. Most of the time, what people would see are items that are above 100k, but not all of them want expensive food items. In fact, some of them can even be under 1k! One only needs to know how to feed these Kadoaties well and quickly, because alot of people like to feed these petpets.
See this avatar here? You can get it too, just feed 75 Kadoaties! ^___^