At 7 weeks for some types of turkeys it kind of hard, Usually at around 15 weeks it's a lot easier to tell for a heritage type turkey. At this age the size of there feet and legs is usually the easier. Males usually have larger feet and thicker legs at this age, but it's still kind of hard to tell for some.
At this age there is a few clues, but when they start to loose the down on top of there heads is about the time the male and female start to look different. The males feet and legs usually appear larger then females. The males snoods will start to get thicker the female will be small and more dainty. The males carnuckles will start to show sooner then a females. As they get older the females will have a strip of small feathers down the top of there head, Males will not but this is kind of one thing not to use until they get older.
They will be fine with out the snood, Last year we had one female got here foot caught in some wire i didn't get removed from there pen, the rest of the turkeys tried to get here free. As a results of that she lost here snood.
Tom