I tried a preliminary round of sexing today, and I think it was pretty successful. From what I could read, males should probe to about 7 subcaudals, whereas females should be closer to 3. Because of the invasiveness of the procedure, and the proven willingness of some babies to bite, I opted to use a clear plastic tube to restrain them. The tube I used is about 1/2 inch thick and about 18 inches long, and blocked off at one end. It proved to be just right for this size.
They were surprisingly easy to get into the tube. As usual, I scooped them out of their tubs with a hemostat, and while they were perched on that, I would approach them with the tube. I found that I could slowly place the opening of the tube at their nose and wait for their natural inquisitiveness to kick in. Once they started to peer inside, a gentle tickling of the body or shaking of the hemostat would cause them to attempt to escape into the tube, and once inside, they were a lot easier to manage. I will say, though, that anyone attempting this procedure should prepare for a stinky mess, as they protested as much as they could from the other end. Have a paper towel ready.
I opted to start with the pinkie eaters and troublemaker groups. I will monitor their reaction over time (whether or not they eat on Tuesday), and depending on how well they handle it, I may also do the holdbacks in the next few weeks. I opted not to do the holdbacks now, as they have missed 2 meals in a row and I don't want to risk missing another. T3 was also spared, as he just took his first unscented pinkie this week and I didn't want to risk undoing any of that progress.
T1 was surprisingly cooperative, considering past reluctance to be handled. As T1 was the first that I tried, it took a little while before I got the hang of handling the tail, inserting the probe, and applying the right amount of pressure in the right place. Also, it took a few tries before I was confident that I had my correct answer. T1 probed to 4 subcaudals, which in all likelihood puts her at female, though I feel I should follow up on another probing in a month or two just to make sure.
T4 was also fairly cooperative, and since I had a better idea of what I was doing, didn't have to cooperate for very long. T4 probed to 2 subcaudals, and barring some screwup on my part, is definitely female.
The pinkie eaters were somewhat less inclined to the procedure. There was a lot more striking at the tube (and me) and attempts to get away from the hemostat. Hard to blame them, though, all things considered. I have given them numbers (P1-P3), as they have individual information that I need to keep track of.
P1 was the easiest of the three and quickly probed between 2 and 3 subcaudals, a definite female.
P2 was considerably more difficult, but probed to 2 subcaudals and is a clear female as well.
P3 was by far the trickiest of the five. There was a lot of snapping and musking and attempts to intermittently flee and charge at me, however, even P3 was fairly easy to get into the tube once he calmed down a little and peered inside. P3 probed to 7 subcaudals, and as such is definitely male.
This worked out pretty well, as the pinkie eating group is the most ready for sale. Assuming there is not some major stress reaction from the sexing process, I'll be able to post them for sale as a breeding trio in the next couple of weeks. T1 will likely need to be probed a second time before I can confidently claim her as female, but T4 is certainly a girl as well.
I have included a picture of T4 in the tube to help illustrate the process.