cubs, those are not designed for penetration, but rather a really powerful whack and some cutting blades to boot.
Where did you hit, and what bow weight / arrow weight are you shooting ?
One fault I find with that and the judo is . . with the arms sticking out, they tend to catch on grass and brush on the way to the rabbit. Unless the animal is in the wide open, I have issues with that. Hex heads, or even old nutters are my choice for bunnies and skwerls.
Also, you need to hit them in the front. . head, neck, front of chest.
ChuckC