There is a little known fact. You can determine the sex of a turkey poult with about 98% accuracy on the day of hatch. Most people do not know this but if you have ever worked in a connercial hatchery you learn. Back in the mid 80's I worked in a Cargil Hatchery as a "Sexpert". It is a nasty proposition but if you want to know what you have then it is a neccessity. The hatcheries must seperate them so that they can send the toms to one house and the hens to another for growing.
I will explain first and then if I can get someone to help me with pictures I will post them later. You can check them as soon as they hatch. In the hatchery this is when we sexed them.
Take a poult in your non-dominate hand and hold it upside down with the tail toward you. Using your dominate hand place your thumb on at the tail and your forefinger on the other side of the vent, spread the vent toward the front of the poult so that you can visualize the inside. A Tom will have two very definate bumps pop up on the inside but at the edge toward the front of the poult and a hen will have a smooth place that is more rounded and not as defined. After you look at a few you will be able to see the difference.
I just bought 12 poults from a local breeder and they sexed out to be about 50/50