Roast duck seller Henry Tan still shudders when he thinks about August 2004, reports the Singapore edition of Straits Times. Avian flu had hit poultry stocks in Perak and other parts of Malaysia.

At that time, every roast duck sold in Singapore was a Malaysian bird.

"Suppliers cut stocks suddenly by half and we were running at a loss of $20,000 a month for two months. We were afraid we would totally run out," said Mr Tan.

In April, frozen ducks from Taiwan made their debut, and these birds have turned out to be as good - if not better - than live Malaysian ducks.

"I tried them out because I was looking for another supplier other than Malaysia, and they were plumper and the meat was juicier," said Mr Tan, who owns four roast duck stalls in Singapore.

They were so good, and cost him no more than a live duck, that he now buys about 1,000 Taiwanese ducks a month, and 5,000 Malaysian ducks.

He plans to buy more frozen birds.

"These ducks are cleaner so I don't have to spend as much time to prepare them for roasting," he explained.

Sourcing new supplies of frozen ducks, and other kinds of food, is part of the Agri-Food and Veterinary Authority's constant efforts to diversify Singapore's food sources against a backdrop of unpredictable crises.

The outbreak of bird flu was one. Most recently, climate change and soaring oil prices have had adverse impact on global agricultural supplies.

"It is always good to diversify because if one source is down due to factors like a disease outbreak we can always look to another source," said AVA spokesman, Goh Shih Yong. "It is also good for competitive pricing," he said.

Mr Tan pays less for his frozen ducks than live ones, by about 50 cents per kilo: $5.40 per kg for a Taiwanese duck against $5.90 per kg for a Malaysian bird.

The savings on the ducks have gone towards offsetting rent increases at his four hawker stalls.

Rents have gone up by about $800 a month for his stalls. The $500 savings he gets from buying the frozen birds cushion that blow so he has not had to raise prices for customers.

Likewise, Pin Corporation, an importer of frozen ducks, has stopped buying ducks from the United States, previously its main supplier.

It now buys the cheaper Taiwan frozen birds.

Pin Corporation's managing director, Liew Yew Fah said the frozen ducks are juicier because they are given more time to fatten up before they come to market.

The ducks are reared for 70 days before they are shipped to the slaughterhouse. For Malaysian ducks, the time period is 60 days.

Mr Liew said his company now imports 7,000 ducks a month from Taiwan - up from 5,000 in May - and plans to increase that number to more than 10,000 a month.

Previously, frozen ducks were imported from the US, France and the Netherlands. But these ducks could not be roasted as they were not fat or robust enough. They were also much more expensive, at about $6.50 per kg.

Singapore imported 6,885 tonnes of duck in the first half of this year. Of that figure, 521 tonnes were frozen.

The number might increase, as importers realise better margins from Taiwanese ducks, coupled with good response from customers.

"Frankly, if it tastes good, I really don't care if it's frozen or not," said Stella Lim who eats at Johnson Lock Roasted Duck & Chicken in Havelock Road once a month.