Kibble is a kind of animal feed. It is inedible to humans. It can only be made by a cook at a butcher table. No minimum cooking skill is required to create it. The recipe requires 1 unit of nutrition from vegetarian items (20 fruit or vegetables or haygrass) and 1 unit of nutrition from meat and/or animal products. A completed bill produces 50 kibble. Kibble restores only 5% saturation, but up to 20 can be consumed in one sitting. Kibble never spoils if it is under a roof, so kibble is a long-term and easily stored way to feed large amounts of animals.
The most efficient way to create Kibble is to use haygrass for the vegetable, as it is the most plentifully generated vegetable component. Kibble is also an effective way to use insect or human meat, both of which will give your colonists bad thoughts if incorporated into their diets. However, if you happen to lack both of these - Kibble is generally not very cost-effective with a mere 25% net nutrition gain from its ingredients, and only really useful as it's made in bulk. Otherwise, Pemmican will generally make better animal feed (although it doesn't last indefinitely), as it has a significantly better net nutrition gain of 80% over its ingredients.
In Alpha 16, Kibble will also be consumable by Humans. However, this will provide a strong negative moodlet.