A rescue centre was at the centre of an undercover TV investigation alleging animals were kept in poor conditions.
BBC Wales' Week in Week Out reveals footage shot by a volunteer at the Capricorn Animal Rescue centre in Padeswood, near Mold.
The programme claims to have uncovered dirty conditions, including in the cattery where the volunteer was said to find full litter trays and diarrhoea on the floor.
But charity founder Sheila Stewart refuted the allegations aired in the TV show.
The programme also claims to show overcrowding, poor disease control and animals sometimes not having access to water, including a rabbit pen.
On another day, the programme finds a pen of chickens with no water and when she fills their bowl they drink for eight minutes.
The centre has already faced an online petition protesting at welfare standards.
Ms Stewart said: “We have water bottles outside and inside the hutches for the rabbits. The volunteer failed to check the inside of the hutches where they would have seen bottles of water for the rabbits. Water bottles are refilled daily.
“Also the point of volunteers is to go round checking to see of bowls or bottles are empty so they can be refilled.”
She added the centre had volunteers to change litter trays and clean up areas.
In one case the programme claims a cat pen was not cleaned for three days, an allegation refuted by Ms Stewart, who claimed pens are cleared every day.
Programme makers said the volunteer went undercover at the sanctuary over a period of 10 days and at the time there was one member of staff and a handful of volunteers working there.
Ms Stewart claimed the volunteer worked for a three day and a four day period, working a total of 21 hours over two weeks.
The programme showed the undercover footage to vet and animal welfare expert Mike Jessop.
He said: “Some of the lack of water is truly concerning – I would be very, very worried about the fact that these animals weren’t having regular access to water and also aren’t being kept clean enough. Those are the key areas that bother me with the footage I’ve seen.”
Mr Jessop added: “The problem is they’ve overcrowded it. You’re then repeating the mistakes of disease transfer, lack of hygiene, stress on the animals - all of which shouldn’t be happening. I would question whether this place should keep going.”
Ms Stewart said: “This is a very one sided negative view of the good work we do here.
“The RSPCA are satisfied with the disease control standards here and the disease controls are checked by vets every two weeks.”
She also says the chickens are checked twice a day and unfounded allegations of overcrowding have been made over a period of 18 months to the RSPCA, but that no action has been taken against the sanctuary.
The RSPCA said it’s been aware of Capricorn Animal Rescue for “many years” and has been working to improve welfare at the centre. But couldn’t comment further, for legal reasons.
On the back of its investigation the programme says there are calls for a new law to be brought in to regulate animal sanctuaries.
It finds animal sanctuaries in Wales - and the rest of the UK - aren’t covered by law, meaning anyone can set one up, and their activities are not regulated. In Wales, there are an estimated 268 animal sanctuaries.
Claire Lawson, an assistant director for the RSPCA in Wales, said: “The number of sanctuaries that we visit on a regular basis where there are problems, suggests the problem is relatively deep.”