THey usually recommend milder woods on poultry like Apple and Cherry. Oak is not generally recommended and I don't know about birch. But, bottom line is you can use whatever you want. I don't think using Oak would by any means ruin a turkey. I have a load of crab apple that I took down in my parents yard a couple years ago and I have used that in the past and will continue to. I reserve the oaks and hickories for beef and pork.