The shrimps don't all hatch at the same time so she may have had a couple of eggs you didn't see. Anyway, it does you a favour as you can check both tanks at the same time as to whether shrimplets do well and better in one over the other etc!
Great to hear all is going well!
Thought I'd update y'all. I stetup the breeder tank and put my 3 pregnant chicks in there. One is done breeding and I've put her back in the main tank, I've counted 9 babies in there. Ironically I've seen 2 new babies in the main tank, not sure where they came from bc I thought I got all the pregnant ones out.
Thanks for your help everyone