It's normal, my sister in laws dog did that all of the time, but it was a snowman candle, but it if bothers you, maybe do some research on fixing the behavior it if bothers you. She just could be very maternal, get her fixed soon....good for you for wanting to prevent unwanted puppies!!! I am pretty sure it has no bearing for going into heat soon, you'd notice bleeding if she went into heat, trust me. I went through that a few months ago.