Chickens are a must for every survival prepper. They eat nearly anything, come home to their coop every night, lay eggs faithfully and adapt readily to new surroundings. With little input from you they will continuously produce both eggs and meat for the family. All they ask is a perch to sleep on at night and some sort of box or basket in which to lay their eggs. Depending on where you live, they may need to be confined in order to protect them from predators (or to protect tender garden seedlings from chicken scratching!).
Since their requirements are few, there are nearly endless options for chicken coop designs.