More than a hundred 'micro-pigs' living in the wild have been culled over fears they could pose a risk to public safety.
It is believed the pigs, made popular by celebrities including Paris Hilton and Victoria Beckham, had escaped from captivity and were living on the 'Welsh Moor' in Swansea.
A council official said they had tried to trace the owners but took the action when nobody took responsibility for the animals.
The pigs were shot after they appeared to have bred with other species of farm pig and it was deemed they could pose a risk to children and livestock.
A Swansea Council spokesman said: "These animals presented a serious risk to other livestock in the region in the event of a disease outbreak, and because of this we were left with no option but to carry out a cull.
"This was carried out by a licensed professional and with full support of local farmers in the area.
"We also liaised with animal welfare officers in the Welsh government to keep them informed of our actions."
The micro-pig trend has been blamed for the situation as many owners may have given the pets up when they became too big.
Despite being called micro-pigs, the animals can actually grow up to 5ft long and weigh as much as 70kg (11 stone).
An RSPCA spokesman said: "Although these pigs are advertised as being ‘micro’, people might not be getting what they think they are expecting.
"Some so-called ‘micro’ pigs may grow to be much larger than expected by the time they reach adult size.
"Anyone considering purchasing a micro-or mini-pig must first consider carefully whether they will be able to provide for a pig’s needs for their whole life."