Q1) Can I get ducks, turkeys, or guineafowl to trigger pressure plates? I ask because I saw an adult duck on what I thought was a minimum-weight pressure plate, but the dog on the hatch cover survived.
Q2) How far do small creatures have to fall to be consistently and instantly killed? Has a formula been worked out, or do we know general numbers?
To explain the odd questions, I'm trying to make a bloodfall. An isolated group of breeding non-grazers inhabit a tall tower with a hole in the middle, a chute going straight down to the middle of my meeting hall. A pressure plate in the same room is tripped more frequently as more animals are born to occupy the room. To ensure the room is not accidentally stripped of all females via chute, another room higher up has a female chained in such as way that she can't fall, but she's incredibly likely to trip a pressure plate that removes all floor tiles she can't stand on.
Alternatively put, the Murder Tower is composed of two rooms: the Abattoir and the Broodmother's Den. Victims in the Abattoir trip pressure plates which open the bloodchute in the middle of the room, sending the lucky inhabitants to their prompt demise. All the while, the Broodmother watches over the younglings from her perch, ever spawning a new generation of supplicants to death to be deposited into the Abattoir.