The term for Chicken-sexer is Byungaree Kambyolsa, which doesn't do a lot of good for the following article, here. The link will tell you that researchers have found a medullary bone inside a dinosaur skeleton, which apparently is a calcium deposit created by egg-laying creatures such as birds. The deposit is used to help make the egg shells hard, which is unique to birds.
So we now know that there is a dead female Tyrannosaurus Rex at a museum at the North Carolina State University. I will sleep better for knowing that!