Well I just finished their rack and got them all set up in it.
One of the holdouts ate, so that leaves me with 3 that have yet to even show any interest. One of the first eaters took the last hopper I had, so that is 3 that have eaten twice now.
As I was moving them into the rack I looked over each one closely and tried my hand at popping them. By my count I have 9 males and 11 females, but I think I missed on one of the first ones. That would make sense because I bet they bag them by sex and one of the bags we got had red marks and the other had blue ones, so I am betting half & half.
It also appears there are 2 - 4 yellowbellies, but I need to read up on them more to be sure.