"We have had to increase the price, and that's due to processes that have had to be put into manufacturing to make sure that the feathers are okay," said one Yonex spokesman. "It has made the process more complicated."

The price increases are yet to have their full impact on badminton clubs, who tend to buy their shuttlecocks in bulk at the beginning of the season.

"It will hit clubs with a bigger bill at the beginning of next season," said Eric Brown, chief executive of Badminton England. "Most clubs order their shuttles around July and August. It will start to hit them then."

Feather farmers

The majority of shuttlecocks are produced in China's factories which either cut and clean the feathers themselves or buy feathers prepared by feather farmers.

Changing dietary habits in China have also contributed to the growing shortages of goose feathers.

"Chinese people nowadays are tending to move away from eating goose to eating duck, and that has affected the farming of goose feathers," Little of Yehlex said.

Natural problems such as droughts and floods in various parts of China over the last few years have also led to a shortage of birds.

Increased labour costs and a growing internal market for shuttlecocks in China have added strain to prices.

"China has also started consuming shuttles now... so this has put a new pressure on the supply of feathers," said a Yonex spokesman. "A whole new market has opened up, as the Chinese start to consume their own products as opposed to just exporting."

The International Badminton Federation said they were encouraging research into developing more advanced plastic copies resembling the feather shuttlecocks, which could be used in the event of a serious shortage.

"We're trying to move towards plastic shuttlecocks," a spokeswoman for the federation in Kuala Lumpur said. "We're hoping to find an alternative as soon as possible."