Funny you asked this as friend of mine 2 weeks ago hatched twin turkeys under a broody.Would post link to his pictures but you have to be member to be able view anything on that forum.So the answer to your question is yes possible but very rare
The chicks from video surviwed and had growed in to a hen and cockrel
I used to breed and show Foreign Finches and a few times had 5 chicks from 4 eggs. The "Twins" Never really made up to anything good for the show bench though.