Looking for help with my little bantam hen. She has been acting funny for a week or two. Today I noticed this crusty buildup on the side of her beak. I don't want to hurt her so I didn't touch it. Any clue what is going on?
Have a look at this thread - see if you can get her to open her beak and see if there's pus etc on the inside of her mouth. I'm not identifying what your hen has as one or the other, but this thread discusses various causes of this kind of thing as a good starting point: