Yep - a 20g mouse should be right smack in the middle in the 10-15g range for the two larger squirms, and quite a bit larger than that, about 25%, for the 81g male - but he's long and skinny, and takes them with no problem at all and a great deal of excitement, which makes me think that he needs a bit more to get some meat on him. I use the 10-15g rule in general for my snakes (except the Kingsnake, who is another matter entirely). I was just surprised that they were so voracious, so soon - really more like three days from their last feeding, rather than four. The little guy, Lue, had a pee and a urate yesterday as well - his first since he arrived - with no poop at all.