I re-read your post... it was Sydney being in the foreground that confused me! Your barred rock GAINED altitude??? Partway through her descent? That is crazy, she must have been channeling her inner leghorn, and Daisy was clearly looking out for her!
IKR!
Yes it was absolutely improbable, yet it did happen. I'm assigning it to the fact that she is still a pullet. Nothing else makes sense.
Certainly that's it! A full-figured BR hen is just not compatible with ascending flight. I hope Sydney doesn't have to learn this the hard way in some future attempt.