Perishability is a factor. Other factors are start-up cost (e.g. chickens require building a coop), time, and preferred taste (some things just taste better fro

Perishability is a factor. Other factors are start-up cost (e.g. chickens require building a coop), time, and preferred taste (some things just taste better from a store and some are better homemade). The book is more of a fun read. There's some funny anecdotes about trying to raise bees and chickens.