My Mum bought me and my brothers a butterfly raising kit from Insect Lore, where they send you caterpillar eggs by post which have usually hatched by the time they arrive. The caterpillars come in a little container which has the caterpillar food in it. There is enough food in the container to last for the whole caterpillar stage! Once the caterpillars have formed their chrysalides, you move them to the provided butterfly enclosure. After a while, they will turn into magnificent butterflies so you can observe them. When a few days have past let them go! So in short, Get’ em, Grow’ em, Set’ em free!