I second the Craigslist search[ what I've done], with maybe Facebook marketplace as another possibility. You'll get a much higher hatch rate if you buy eggs locally over having them shipped.
Dissect along her neck/cervical spine to see if there is a fracture or dislocation. The ruptured yolk may be from the trauma that broke her neck.
Are you in an area with avian flu?
I would put her under the broody hen tonight. I'm far from an expert, but 2 weeks is a big enough of a difference in age I think this one would get picked on a lot and not do well.
Good- Bye and Bee Well [ from a beekeeper, not a spelling mistake].
I didn't yet read all of your posts, but have enjoyed the ones i have. Thank you for sharing your knowledge and insights. I hope life gets better for you and your family.