I had several rabbits, some in breeding, and two others, as a pet. It's very fragile. The small farm suffered from Taenia and mixomatosis. I prefer to avoid you the subject of my methods to prevent them from suffering. You have surely discovered that the rabbit has two types of sleep: a classic sleep, and a trance sleep.
It is a sleep that allows him, like the dolphin, or the hen, to monitor a predator, while resting his body, and mind.
His eyes stay open a little more than normal. Blinks still run. The pupils constrict as much as possible. Thus, the brain sees a blurred image. But a tiny part of the brain remains functioning to alert if a specific type of blurring change occurs.
The animal sleeps in a trance. He is having fun during this moment. His mandible shows this pleasure by activating the salivary glands, swallowing his saliva and blinking his eyes. All these minor actions occur almost simultaneously so as not to attract predators.
The body also contracts, in synchronization. This is to maintain the animal's temperature. The heart is solicited in a specific way. So, at an advanced age, this trance state can lead to eternal sleep.
In rabbits, the ultimate eyes open are not always synonymous with suffering, on the contrary.
On the other hand, it is a curious animal with no instinct for self-preservation against the maze of contemporary architecture, so I remember having to smash a wall with a hammer, make a big hole to slip into a condemned dark room, recover, by hand, the stuck animal, then having rebuilt the wall, up to the tapestry.
Hoping that your pet is gone in this trance full of dreams and pleasures...
Binary Finary 1998