A grandfather watched on as he sated an alligator’s appetite with a much-loved chicken known as Betty White, but afterwards apologised to wildlife sanctuary staff.

Peter Smith reached over a concrete rock wall at the regional NSW sanctuary and grabbed the white Chinese silkie bantam chook before putting it inside his shirt, court documents reveal.

He walked through the reptile exhibit towards the alligator enclosure before throwing Betty White into a pond where two 2.4m-long alligators were lurking.

Smith, 58, of Hunterview, pleaded guilty on Tuesday in Raymond Terrace Local Court to one count of aggravated animal cruelty on January 2.

An agreed statement of facts says the two alligators at the Oakvale Farm and Fauna World, a family-owned sanctuary home to a menagerie of native, domestic farm and exotic animals at Salt Ash, “immediately made their way towards the chook with one of them snapping the chook into its mouth, killing it immediately”.

“The accused [Smith] stood next to the fence observing the incident occur.”

Betty White’s untimely demise took place in front of shocked visitors who alerted staff.

Park owner Leanne Sansom reviewed CCTV footage and gave a description of Smith to staff members who tracked him down, and he apologised.

Police went to the park the next day, where Sansom handed over the CCTV footage and told them how Betty White had been hand-raised.

Smith turned himself in at Singleton Police Station on January 4, when he gave a statement admitting to grabbing Betty White and throwing the chicken into the alligator enclosure “with the intention of feeding the alligator due [to] its living conditions”.

“He [Smith] stated he shouldn’t have done it,” police said.

“I was really disappointed in myself,” Smith told police.

Defence lawyer Bryan Wrench told the court on Tuesday the case was a “very unusual matter” where Smith had simply fed a chicken to a hungry alligator.

He said there was the old adage “never smile at a crocodile”, but this was a happy alligator after feasting on Betty White.

The defence lawyer said Smith had no criminal record, was a grandfather, had grown up in the country and “just wanted to feed an alligator”.

Magistrate Kirralee Perry said she was not sure making light of the situation was the most appropriate approach.

“These are serious allegations,” Perry told Wrench.

When told the maximum penalty for aggravated animal cruelty in NSW is two years’ imprisonment and a fine of $24,084, Perry said: “Nothing to make fun of, then.”

Wrench said he was not making fun of the case but 750 million chickens were killed each year.

Smith’s case was adjourned to November 20 for sentence.

He refused to comment outside court.

In a statement released after the silkie hen was killed, Oakvale Farm owner Kent Sansom said management and staff had been deeply saddened by Betty White’s fate.

“This is the first time in our 43 years that we have had a member of the public [allegedly] engage in such cruelty in what is an animal sanctuary,” Sansom said.

“Betty White was hand-raised at the park and had played a crucial role in our endangered species breeding programme for the bush stone curlew and other species by providing surrogacy to the chicks.

“Her quiet nature means she would not hesitate to approach a customer for some animal pellets, making her an easy target for [an alleged] ruthless perpetrator.”