We’ve swapped with fellow chicken owners, employed some neighborhood teenagers, and imposed upon our cat sitter for chicken care, all with fine results. There are also professional “farm sitters” in Seattle. I think there’s one who lives in the Admiral District. She advertises on the Seattle Farm Coop’s email list during Market Friday.
The Seattle Farm Coop is a wonderful resource in general: http://www.seattlefarmcoop.com/