What is going on with egg prices in the US? Bird flu chicken slaughters?

In NZ a law was passed requiring all chickens to NOT be caged (barn with some amount of outside area, if not quite free range). It came into force on Jan 1 last year or the year before I can't recall. And eggs shot up from 30c to $1.30 or so (my guesstimates) but have since come back down to around 60c.