Yes, if you have a parasite infestation it can cause a bird to stop laying. If you think you have bugs, treat all your flock because what one has, so do the others.
Also, if there is a flock change, i.e. adding new members, that can stress a bird and cause them to quit for a while. Just check to be sure she is not being bullied by the new additions.
Hope that helps. Good luck.