Two mamas, one 4x3 cage, and a whole lot of feathers about to fly. That's the real question here, and honestly, it's the kind of egg-citing drama we live for. Our take? You're probably fine, but you're also playing a game of fowl roulette with a very small cage and two very protective moms. The real enemy isn't each other, though, it's the rats, and you're already one step ahead by moving the new clutch to safety. That's not chickening out; that's smart parenting.
Let's break this down. You've got one hen with month-old chicks who's already used to her nighttime routine, and a second hen who just hatched maybe three, maybe four, new babies. The grow-up cage is 4 feet long, 3 feet deep, and 2 feet high. That's enough room for a polite dinner party, not a hen house sleepover. Hens can be territorial, especially when they've just hatched. The older mom might see the new mom as a rival for space, and the new mom is running on pure hormonal adrenaline. They probably won't fight to the death, but you could wake up to some serious pecking order drama. We've seen how Feathered Friends or Fowl Play: Can You Crack This Mystery? goes when you can't even tell who's who, and this is a similar puzzle with higher stakes. You're not identifying breeds here; you're managing two mothers with very different agendas.
The practical move is to give them a divider. Even a piece of cardboard or wire mesh down the middle of that cage will let them see each other, smell each other, and cluck their grievances without making contact. That's not overthinking it, that's preventing a midnight brawl. And if they do seem calm after a few nights, you can try removing the divider and watching them like a hawk. But don't do it on night one. Night one is for survival, not social bonding. You've already got a rat problem that's eating eggs and chicks, so the last thing you need is an injury that sends one hen to the infirmary and leaves the other chicks exposed. Remember, Hilda and Beaky fight over shotgun in Joyce the campervan's favorite roost shows that even the best of feathered friends squabble over prime real estate. Your cage is the roost, and there's no shotgun to distract them.
Here's the concrete takeaway: separate them tonight, even if it's just with a temporary barrier, and check on them at dawn. If they're both brooding peacefully, great. If not, you've bought yourself time to figure out a bigger solution. And keep that rat control front and center, because no matter how the hens get along, a rat doesn't care about your coop politics. It just wants dinner. You're doing the right thing by locking everyone up tight. Now just make sure the only fowl play in that cage is the kind that ends with everyone alive and clucking in the morning.