If you have no roosters then the other hens are picking her head bald. Try keeping her in a cage inside the coop for a couple weeks till she heals, if possible. That way the other birds get used to her being around but can't hurt her.
How are you keeping these birds? Both bobwhites and button quail breed naturally in pairs and when you change that problems tend to ensue. Keeping a large aggressive species native to the US with a tiny aggressive species native to China is not a good idea. Quail are extremely territorial and...