I'm not really sure, I have this feeling WC patched the game at some point and made poly farms unworkable, but I can't really remember.

Used to make them this way. 2 level structure with hatch frames to make the second floor, 2x2 foundations. Wandering moschops on the ground level, a few penguins up top breeding away. Penguins are their own air cons, so babies are born and start wandering, they fall through the hatch frames and starve to death, the moschops auto harvests the dead bodies.

As to settings it's been years since I made a poly farm, I think when I did it I was basically playing on default SP apart from harvest and tame. I can't get a poly farm working at all these days because I boosted my maturation settings and play with PVE settings on. You'll probably need to be playing PVP with friendly fire turned on.

Main issue with settings that are boosted past default is making sure the babies die quickly enough to prevent them having access to any nearby feeding trough and surviving. So normal food drain, near to normal maturation settings as you can stand.

One other issue I used to have was that it could be awkward actually getting the babies to reliably fall through the hatch frames.. but now that I think about it WC have made that easier for us, just remove some of the ceilings that make up the second floor entirely since the penguins no longer need to wander themselves to mate. They'll just sit there watching their babies fall to the ground floor.