Add a filter feature to the critter sensor (or add a filtered critter sensor as a separate building)

[nicvampire_1]

I usually manage my critter farms by using critter pickups and dropoffs. For each critter I'm farming there is a dedicated overcrowded room where all of them hatch, and whenever the main farm loses a critter of that type, a dupe will come to a critter pickup in the critter storage room and collect that critter to carry it to the farm. Easy concept used by a lot fo players, nothing too complicated. However, that creates a problem in that the way a critter pick-up works is it will make dupes pick up critters even if that's not needed, which wastes dupe labour. 
That can be fixed by putting a critter sensor to all of the critter farms and connecting them to the critter pick-up in the critter storage room. A critter pick-up will only work when the amount of critters in any of the farms is below the maximum amount they can handle. That generally works pretty well for a single-species farm.

However, because a critter sensor cannot be selective about which critters it scans for, there can be problems with the farms that have different species of a critter in one room. Puffts are one such example from the base game, although in their case puffts and prince puffts can be split if we don't need any other morphs, but if we want prince puffts and normal puffts to be in one room for the morphs, there may appear a problem that when we need a new prince pufft, a duplicant will go and pick up a normal one instead. This will not break the farm since the critter drop-off does allow us to be selective, so we can add a drop off for each critter, but fixing this with critter sensor isn't really possible because of that. 

A better example of this are the new orehulls with kelpoles. Sure, we can separate kelpoles and orehulls and feed the orehulls nori instead, but it does feel like they are meant to go together, since that allows to save some space. But if we make a separate confinement with a new aquatic critter pick-up for the orehulls, there won't be an easy way to make the pick-up not work when we have enough orehulls, because a critter sensor in this case will also detect the kelpoles. Having not enough kelpoles for the orehulls would partially fix this, since the kelpoles would be spawnkilled by the orehulls, but it would be better and easier, if a critter sensor could detect orehulls and not kelpoles to manage this.