I'm completely new to turkeys here, and still unsure as to when and how (and the science behind) to tell.
Been reading from a few different sources now that it's sometimes possible to decide based on head shape and size of snood bump (is that what it's called?), while others feel it's best to wait things out. I've been noticing my Bourbon Red has a much larger, squared head, and more pronounced snood in comparison with the Royal Palm's triangular head and tiny snood. Perhaps this is due to the fact they're different varieties? Any opinions for a novice like me? 
Bourbon:
Royal Palm:
Together:
~Alex


Bourbon:
Royal Palm:
Together:
~Alex