For me, I don't separate out birds unless they are getting severely picked on or are so sick they just have to be placed somewhere else.
I'd re-check that crop first thing in the morning to see if it's emptied. If it's not, then begin treating as sour crop according to the article linked...
@tripletfeb gave you the correct info. An adult hen's body temp ranges from 105-107F so I wouldn't necessarily declare 106F a fever.
How is your hen acting? Lethargic, not eating/drinking, hunching....?
How old is she?
Does she lay eggs?
Photos of her and her poop would be good.
You have...