Why are wild pigs in California turning blue inside?

[Catherine]

You are right, here has to be a kinder better way than poison. Once that poison is out there in the environment, it just keeps on killing.
The wild hogs probably ate rodents that died from the poison. That means other animal have eaten  poisoned rodents. 
The wild hogs are pretty tough and they tolerate a fairly high poison level. Owls and hawks would not be so lucky.

I have heard of the ultrasonic repellers. It sounds like they work very well on rodents and they do no harm to anything else.
It would certainly a less cruel and less dangerous alternative.