Is that a heat lamp bulb in that case?The picture of them on my hand is the very first day I got them and the picture of them in the brooder is one I just took. Okay, maybe not QUITE double her size but enough to definitely raise an eyebrow. She was noticeably smaller when they arrived.
This is a big size difference.
Is the person that gave them to you sure these birds were hatched on the same day?