I had a girl go on strike for 2 full weeks. A bit less than yours however. I don't know if it is normal or not. My girl seemed perfectly fine all along and then started laying again.
If you are not seeing feathers everywhere from her, (molting) she could be going broody. Broodies stop laying. Make sure she is getting enough protein. Even though your other girls may be laying well on their layer feed, she may not be processing enough of it to produce enough eggs. You could try offering her hard boiled eggs everyday to boost the protein levels.
Has she been wormed recently? A pale face, comb and wattles...diarrhea all can indicate worms. Check her over for mites. They can drain a bird a bit to get them to stop laying.
If none of this works, and she continues to act completely normal, then maybe she is just on strike for a while.