A: It would be perfectly normal if you lived in the 1830's. Back then there was a company that sold rats soley for the purpose of crawlin' in yer pants. This was before man invented stripers, so that's how they used to get their yaya's. Yes, there was occasional nibbling involved, but that didn't stop anyone!
Q: Why would Grig want to bite off the head of a rat that's doin' him a favor?