Mrs Shanker said the ponies have been kept at the Horsecity building since the middle of last year.
Before that, they were kept in nearby stables, now leased to Paisano Polo Academy.
She said that the building's ground floor was being used for "storage". The second floor houses mares and the third floor stallions.
Asked why some of the animals appear thin, she said: "We have since noticed one or two ponies (that) are off their feed and have instructed special attention made to them."
She said the animals are fed hay five times a day, and that they are "showered weekly and groomed daily".
"They are walked around the stable if the weather is bad and otherwise let loose in the paddocks," she added.
As for a pony seen roaming about the building, she said it could be an escaped pony "loitering around the premises".
Horsecity opened in 2007, offering riding lessons to the public. It was developed by Blue Dolphin Gallery, which owns Gallop Stable.
Formed in 2003, Gallop Stable also has stables and offers riding lessons in Pasir Ris.
It keeps 67 horses and 91 ponies in Singapore. The horses are mostly former race horses, and the ponies are bred in its farm in Malaysia. Mrs Shanker said four employees attend to the ponies there.
She added: "Cost has never been an issue with maintaining our horses as their welfare comes first at Gallop Stable."
The cost to upkeep a horse is $1,500 a month and $700 a month for a pony, she said, adding: "AVA is fully aware that we have ponies located in the building. Routine checks are done by AVA."
Once the ponies are relocated to the new premises, the building will be converted into a riding academy with accommodations and classrooms.
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