I'm thinking dog house instead. Back Yard Chicken Coop with roof garden, no reason why you can't use pallets for this project. However a word of caution,use heat treated pallets and not chemical treated ones as the chemicals do leach out and can cause problems for animals, birds and your chickens.
Surrounded by raised garden beds, this deluxe chicken coop has what it takes to keep chickens safe, healthy and laying fresh eggs: a minimum 4-by-8 foot screened-in run and a 4-by-4 foot critter-proof coop for up to three hens. | Photo: Matthew Benson | http://thisoldhouse.com