Whilst it looks shocking and the way it is done is cruel and should be outlawed, I can't help but wonder about other forms of this behaviour.
Fox hunting, Wild Boar hunting using dogs to tear off their ears.
Then there's catch and release fishing, if you aren't going to kill it humanely to eat it, then don't put it back in the water for sport with a hook ripped from it's jaw or mouth. Yes, they do feel pain and shock.

Rabbit and mouse poisoning on farms.
They endure an agonising slow death, sometimes for days at a time.

With any animal, why not kill it as humanely as possible.
If a greyhound catches a humanely killed rabbit, the greyhound still learns and the rabbit doesn't suffer.
Possums are a protected species, so these trainers could face very hefty penalties!
What shook me more than anything was the pleasure they took from the cruelty.
Would you want your greyhound trained by people like this!
Just my opinion.

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