My boxer is in her 2nd heat about 14 days into it. She is having a bad smell coming from her is that natural
well I'm sure you would smell if you were in heat too...
you should give her a bath. Sometimes dogs in heat just don't have that instinct to clean themselves, so they will smell.
if the smell persists, take her to the vet.
NO it is not, have a vet see her.