Neighbour Aimee Murray said it appeared Putz jumped the fence on Friday to be with its mate "and the two have been out roaming".
"He was home at 7pm on Friday night and in the morning he was gone - he had broken his collar at the chain," she said.
Putz returned early Saturday morning with a bloody ear and Primer returned Saturday evening with a bloody face.
"It has long hair and I couldn't see any pellets at all through it," Ms Murray said of Putz.
"I had no clue it was shot in the face - I thought it had been fighting another dog. Even the vet didn't say anything until after she shaved all his hair away for surgery and saw hundreds of pellet holes.
"The main thing is he is not going to die, but still ... it's not good.
"I am assuming he has gone roaming with the next door neighbour's dog because they are quite pally, but it could have been done separately because my dog came home injured lunchtime Saturday and her dog didn't come home until about 10pm.
She said to shoot Putz in the head was "malicious".
"My dog shows no aggression to anyone - it is a lovable pup that doesn't look aggressive and you could have given it a warning shot. You didn't have to shoot it in the head.
"The police automatically assumed, because it was school holidays, it was kids mucking around. The other assumption is they went into a farm paddock. I don't see that happening - my dog doesn't roam that far."
Vet Services vet Sharne Boys said there were hundreds of lead pellets remaining in the dog's head.
"It was mainly the left side of the face where the ear was a bit macerated and there was damage to the eye."
She said Putz might lose his ear but probably retain his hearing.