ATWATER, Calif. — Hens in California are living the good life. Many can now lay their eggs in oversize enclosures roomy enough to stand up, lie down — even extend their wings fully without touching another bird.

Hens in most other states don’t have it so good. Their conditions, as the head of California’s egg trade group explained, are “like you sitting in an airplane seat in the economy section all your life.”

So if you’re a hen, you want to live in California. Short of that, you want California-size leg room. And that’s precisely what lawmakers in California are demanding of out-of-state farmers who sell eggs in California — setting off a feud over interstate commerce that has spilled over into the farmyard at large.

The Missouri attorney general has filed a lawsuit to block the California egg rules, and at least three other states are considering doing the same. The beef and pork lobbies are also lining up against the California rules in an effort to prevent any new restrictions on raising livestock.