What is the chaces of my dog getting sick from killing a rat , he did not eat it just killed it ? He may or may not be up on his rabie shot not sure if he is due it isn't by much. And I still have the rat should/could I get it checked out.

Leptospirosis is a BIG DANGER to dogs in my area. Was your dog vaccinated against it?

I'd call the Vet and ask.

You don't know if the rabies shots are up to date? "Ain't by much" or not, overdue is overdue.

Then, yes, you NEED to ask your Vet. Chances are slim, but I wouldn't take the chance.