swollen lump in eye area

One of my chickens has a swollen lump in the red skin area by her eye.  I can't see broken skin.  Might it be infected, does she need antibiotics?  Or has someone pecked her? 

She also has tiny bits of yellow yolk like stuff on her feathers in the same area.  I think this might be a red herring, as it looks so much like egg.  Or could it be infection, it is very bright yellow?

Any help will be greatfully received.
Thnaks.

Thank you for the quick reply.  Will she be alright till friday, as I have to go to the vets with another chicken then.  Or is sooner better?