I am playing A20 "stable alpha". I took some of the chickens from https://github.com/doughphunghus/7D2D-EntityRandomizer/tree/master/Pre-Generated-Modlets/Doughs-RandEnts_For_a19.5.b50_vanilla-friendly-animals-only-400-clones and it gave a red errors about the AI not existing. I'm at work so I can't give the exact error. I also don't know enough about the AI options change from A19 to A20 to have any meaningful discourse.
It is impressive that you did it in Perl, I haven't touched Perl since 1996!