Hey Bob, how have you been? Hope you had a nice Thanksgiving.
The first Boa I ever bred was Big Momma, and she did the same as your girl in question. I think I understand it a little better now....than, then.
The first ovary ovulated, and then a month later the second one fired off. Hopefully she will have retained sperm for the second ovary.
My girl produced 13 healthy babies, one premie undeveloped and 26 slugs....also had 2 sheds, but the count went from the first shed.
I am guessing, but the second ovary had no sperm for producing viable babies in my girl and that is where the slugs came in....could also explain the premie undeveloped baby that I had to put down...it could have been from the second ovary, and not enough time to develope.
Hope this helps, and good luck with that girl. Andy