I haven't been getting any main quests for some reason. Erevi has been pregnant for ages and still not given birth. The walkthrough say the Rats! quest is next, but the never triggered.
EDIT: okay, turns out you HAVE to sacrifice at least one bat breeder to continue...
A BB sacrifice isn't needed to trigger "Rats." Just raise her Affection high enough, plus she must have announced her pregnancy. Two black goblin sacrifices net enough Affection for that. (FYI Erevi announces the ED pregnancy on day 4, her other pregnancies announce on day 5. For all girls the day you knock them up counts as day 1 of pregnancy.)
I usually bring her a black goblin immediately after receiving "The Lord's Work," go capture a BB and keep it, and head back to town to buy the contraptions. I go back to the Tower right after buying them, nabbing another black goblin on the way and giving it to her, and use the contraptions to start on egg production.* The next time I visit the Tower Erevi should announce. (I also give her another sacrifice before asking for more sex and receiving "Rats.")
*As soon as the BB is in her cell I activate better rations & upgrade the cells followed by the BB Affection cheat to max her Affection, then give her an orgasm using the contraptions to trigger "Man Cave." Aside from getting an alchemy station at the Tower, you can use couch sex instead of the contraption minigames for egg production.
