[theBCnut]

That is how some dogs react to being given their hearts desire. It’s called resource guarding and it isn’t something you want to encourage. If she has never done it before then maybe just a sharp word will be all that is needed to discourage that behavior. For a dog that it is an ingrained behavior, you work at teaching them that when you mess with their food it is a good thing because you give even better stuff when you do that.