You have a hatchery stock Light Brahma! They are a large, pea combed, feather footed breed. They are extremely cold-hardy, docile, and lay large brown eggs. I love my Brahmas!
Her stance has me a bit concered though. Is she hunched down due to being on a slippery surface or does she carry herself that way normally? It looks like she is either in molt or being over-bred (I am leaning towards over-bred with those missing head feathers). Make sure she full has access to calcium (crushed oyster shells) to help her grow back her feathers.