If she keeps growing and is bigger than the others by her first birthday, then you'll know. I don't think hatchery JGs get as large as breeder JGs (more of that representative disclaimer) either but I would still expect *some* difference.
They consolidate bins often and they may forget to move the signs. They also put some together to share a bin thinking nobody could possibly mix those two up but it happens. I saw newly arrived gold laced Wyandottes one day and they hadn't changed the sign from the previous week. I pointed out the error thinking I was being helpful and they went defensive on me saying, "That's what the hatchery said they were." It was something that wasn't remotely similar, why not at least consider that the person telling you this might have some idea what they are talking about and check that day's packing slip?
I think the workers there hear a lot of things from customers. It can't be an easy job. I have sympathy for them. But yes, they could at least check to see if a mistake has been made. Better that way than having customers upset later on over not buying what was advertised as for sale.
