It really depends upon how much it affects the chicken's grown, if at all. I've got a banty with a twisted beak. She does just find eating, though she does have some challenges with picking up things off of hard surfaces (like crumbs off pavement). She's pretty feisty, though, and does ok. She's more likely to have things stolen from her because she drops food.
Your friend should ensure that the feeder is deep enough for the twisted beak bird to eat. This helps in many cases.
If your friend's bird fails to thrive, the bird will have to be culled. In any case, this hen should not be permitted to breed.
