Who stole my eggs???
- The Chiarian
I'd guess a raccoon as well. They're dexterous enough to steal the eggs without crushing them right out. It could be a possum too.
You should confirm by installing a security camera. A wifi IP cam can be less than $50 and capture motion sensor footage. I've done this myself many times to solve mysteries around my house.
As long as the girls return to their coop by dusk, it might be relatively ok at least from nocturnal animals like coons. You always run risk of losing them when free-ranging chickens. My main problem is hawk during day time. I've seen odd coons hang out once in a while during broad daylight as well. Luckily foxes don't come in my property because all my neighbors have big dogs with underground fence.
You'll never know and will always wonder. Install a security cam that with night time IR vision - like I said they're inexpensive, and will pay off in saved chicken feed vs free ranging.
You can set the the cams to alert alarms as well. Solving the mystery surrounding your eggs would be a no brainer for me. I even have security cams installed in the run and in their coop so that I can figure out who's laying eggs.