If she's acting down, then it's probably a good idea to pull it and let her heal up. Might be a good idea to keep her in a quarantine cage in the coop while it heals so she can see the others without being pecked. Lots of treats and pampering for a day or two might help her perk up a bit if...
Best not to pull it out, although it's not a big risk thing to do if you feel you really need to. It will likely hurt her though since it's such a large shaft feather. I would say the safest course of action is to put flour or cornstarch on it as you've been doing and try to leave it as open...