As China celebrates the New Year by ushering in the Year of the Dragon, U.S. small companies with exposure to the country are doing more hand-wringing than rejoicing.

During the Chinese New Year, which started Monday, factory output grinds to a halt as many of the migrant workers return to their home provinces during a two- to four-week period.

Large and small companies have adjusted their business models over the years to accommodate the holiday. But those adjustments have not taken into account new economic trends in China, which are whittling down the country's factory workforce. Fewer workers have meant delayed shipments and lost sales for small U.S. companies, some owners complained.

"Even though we planned for the New Year holiday and ordered early, my supplier in China couldn't get to my order on time," said Andrew Green, owner of GlowUniverse.com, which produces glow-in-the-dark party supplies.

Green ordered 1.5 million glow sticks valued at $80,000 and was hoping the shipment would arrive in mid-January. But the factory said it couldn't make that deadline. As soon as his order is ready, Green said he'll shell out an additional $2,300 to expedite the shipment to the United States. His hope is that the products arrive in February or else he could lose crucial post-Christmas sales during what is already the slowest time of the year for his company.

Other economic trends at play. New labor policies implemented in China have shaken up the manufacturing industry, experts said. In 2008, the government granted more power to factory workers, mandating that employers provide benefits, such as social security and retirement insurance. New laws also made it much harder to fire workers. The increased costs either forced factories to shutter or encouraged owners to work with leaner staffs.

"Ten years ago, maybe we had 20 factories supplying us with glass for our candles," said Mei Xu, owner of Chesapeake Bay Candles. "Now we have five."

Adding to the labor shortage: More peasants -- China's main labor force -- are opting to stay on their farms, thanks to government incentives. Meanwhile, others are going for higher-paying service jobs.

Xu, whose candles are sold in Bloomingdales, Bed, Bath & Beyond and Kohl's, has been importing from China and Vietnam for 17 years. So she knows how the Lunar New Year -- which is celebrated in both countries -- can hurt a small U.S. company. But these newer economic trends are making it even more difficult to conduct business there around this time of the year, she said.

Tired of these challenges, Xu opened her first U.S. factory in Maryland last June. "This will help us bring our products to market much faster," she said.