Rooter lifting gates require that a hog use its nose.
Guillotine trap door trigger.
Guillotine or drop style doors are called single catch doors because once the trap has sprung that is the door has closed no more animals can enter the trap until it is manually reset.
One drawback of guillotine gates is that they do not allow additional pigs to enter once the trap has been triggered.
This is not a continuous trapping door once it s closed it s closed until you come and manually open it or reset it.
Photo courtesy of texas agrilife extension.
Therefore it is extremely important that the trap be strategically baited to insure that most if not all of the pigs in a sounder have entered the trap.
Guillotine or sliding drop gates use a trip wire to trigger the door to fall.