can you get a picture of the gash? I bet she can still make it! My hen was scalped down to her skull- literally feathers, skin, muscle all gone, her beak ligaments were no longer connected to anything so when she ate they just flicked around in the air- my bf thought she was a goner- but within two months she grew back her muscles, skin, and even her feathers. Your hen may surprise you, as long as you can keep her wounds clean she stands a very strong chance of recovery.