On Thursday night, thieves stole 23 goats from a Hawaiian farm and used duct tape on their mouths to keep them quiet. KHON

A full moon may have given thieves ample light to steal more than 20 purebred Boer goats from a Hawaiian farm, but duct tape kept them quiet.

On Thursday night, 23 goats -- most of them pregnant -- were stolen from Kahuku Goats, a 250-acre farm on Oahu's North Shore. Valued at $10,000 the goats were born last week. Some that were left behind had ropes around their necks and duct tape covering their mouths, KHON reports.

“It had to be very traumatic for the animals. They knew that they’d scream, so they were taping their mouths shut and they weren’t small guys. They were huffing them over fences and dragging them down hills,” owner Keal Pontin said.

Pontin suspects the thieves got to know the daily routine of the farm and waited until it was a full moon to steal the herd.

"If you think about it, they're taking nannies with babies in them and throwing them over a 6-foot-tall fence," Pontin told the Associated Press. "Just thinking of our pregnant goats going over a fence like that is just sickening to us."

The majority of the goats were pregnant, 10 of them were days away from giving birth. Six were pets, bottle-fed since birth.

“I’m pretty sure that they sold them for slaughter, which is sad considering that they were pregnant nannies and very friendly nannies at that. So it hurts,” Pontin said, adding that other nearby farms have been hit by thieves.

“It’s not isolated with us. They hit us a lot harder than the other guys,” Pontin said.

Pontin contacted Honolulu Police, who have classified the case as second-degree theft, according to Hono­lulu Police Department spokes­woman Michelle Yu. He is offering an undisclosed reward to return the goats.

“When you take a hit, it makes us want to pack it up and go home. We’re not going to. We will keep at it. We will get stronger and more secure,” Pontin said.

A similar goat theft took place in Alaska in May. Twenty goats and 15 chickens were taken from a farm in Wasilla, Alaska, Anchorage Daily News reports. Some of the goats were pregnant and gave birth to stillborn kids out of stress.

"It's bad enough to have 20 goats disappear, but to walk in and find six dead babies is pretty traumatic," Fritcher said. "It's heartbreaking."