Kevin is correct but it's only for outside temp of the meat. So long as ALL exposed surfaces are above 140 in under 4 hours you should be OK. Normally surface temp of exposed surfaces in a 225 smoker will be safe in an hour or so. And ALL means inside the bird cavity so it must be empty and not stuffed with anything.
Having said that I suggest if doing full birds that you cook at no less than 300F. And for pieces you can do a lower temps but skin will need to be tossed or you won't be serving a quality product. So reality is you need a different cooker for chicken/turkey.
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