Help Save This Injured Kitty's Life

Please help us save this kitty, we found him on the streets with a really bad leg injury, it’s possible he was bitten by a dog or some other animal. He won’t eat or drink and he’s not walking as he’s too weak and dehydrated. Vet needs to run several tests to get a diagnosis so we can treat him. My heart hurts every time I see an injured animal, so we are trying to get him well again, but it’s too expensive, please help. Any little help is welcome