What color do I call her?

I don't really know the coloring horse terms. I always just say this horse is brown. I was hoping you could tell me what color she really is so I can stop calling her brown. Haha. Just a little bit about her, She is a quarter horse, not papered, her name is Penny and she will be 7 on February 28th. I have only had her for about 3 weeks. So if you could let me know what color I could call her thank you :)....I added a few extra pictures of her and my other horse Krissy :)

She is sorrel, or chestnut, it means the same thing. :)
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She's sorrel (chestnut) in my book.
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I'd call her chestnut, I think sorrel would be appropriate as well (but is used primarily by stock horse & Western folks, I believe) The other horse is a black pinto.

Thank you guys!