Sounds more natural.
Since the context is already given that the sentence focuses on 她, there is no need to include extra 她.
This answer should be accepted, IMO. A nearly identical answer, "她生病了，她在房間裡睡覺。" was just rejected for me.
Why is "她病了。她房间里睡觉。“ not right? I understand I don't need the extra 她, but does it need 生? Does it need 在?
在 is needed. she is sleeping in the room, here 在 means “is”
她病了 = 她生病了 = she's sick
i don't think there's a difference