
In poults it is unlikely that hissing has anything to do with the sex of the poult. In adults I have only had hens hiss.
Strutting is not a guarantee of the sex as both hens and toms can strut or display.
At 3 months old most turkey poults can be sexually identified but late developing toms can take 6 months or longer to be able to positively identify them.
Post photos of them individually. For ease in identification one photo should be a full view from the side, one should be a full view from the front and a third photo should be taken from the back including the back of the neck and top of the head. The photos need to be in focus and from a relatively close distance with no obstructions in the way.
Also if you do a search limited to the turkey forum, there are many posts describing how to tell the sex of turkeys.