The character 家 is a bit of a joke: it describes a dwelling (宀) for pigs (豕). Why is this strange construction used? Were pigs somehow important for homes in the past?
说文解字 describes 家 as 从宀，豭省聲 - that is, it uses 豭 (jiā) as phonetic. But then this raises the question: why use 豭 instead of the much simpler 叚 (jiǎ)?
Therefore the author suspects that the character did indeed originally mean "a dwelling for pigs":
But this raises another question: why did a dwelling for pigs come to mean home? By contrast, 牢 (a dwelling for oxen) has come to mean "jail". Was the choice of animal therefore arbitrary, or were pigs somehow more important in the past - did people keep pigs in the house? - or did having pigs in the house signify something home-like?