Though bird flu has recurred in Vietnam and claimed two deaths this year, the sale of live chicken and other fowl that have not been quarantined and tested is still popular.
Authorities have not been taking many preventive measures against the illegal trade, say market observers.
The illegal poultry trade can be easily seen happening in many Ho Chi Minh City locations, especially in outlying districts like Go Vap, Hoc Mon, and District 12.
Along a 200-meter stretch of the Tan Son Street which passes Go Vap and Tan Binh districts, Thanh Nien found nearly 20 hotspots where live and untested chicken were being sold for VND80,000-VND90,000 per kilogram. Ducks were cheaper, costing VND45,000-VND60,000 per kilogram.
On District 12's TMT13 Street, traders gather everyday to form a poultry market where chickens and ducks are sold and slaughtered in case customers need.
Other major illegal poultry trading sites include the Cho Cau, Thanh Loc, and Truong Dai bridges in Go Vap District, and Le Van Khuong Street in Hoc Mon District.
The traders said they bought poultry from Mekong Delta provinces and transported them to Ho Chi Minh City by motorbike or car.
A Thanh Nien investigation on March 17 found that many motorbikes carrying poultry along a section of the National Highway 1A in Binh Chanh District from Delta turned into an alley just several minutes before a livestock quarantine station.
Some others, meanwhile, passed the station at very high speeds to avoid inspection.
Nguyen Thi Huong, head of District 12's Animal Heath Station, said it was difficult to control illegal poultry trade because of the close connections between traders.
She said when the agency's staff inspected a trading site and seized poultry there; traders immediately informed others at nearby hotspots so they could escape.
Huong called on the local police to improve coordination in the fight against illegal poultry trade.
"To crack down illegal trade effectively, we suggest the police keep an eye on the problem more closely.
"Two months ago, we conducted a spot check at a house in Tan Chanh Hiep Ward and seized 449 chicken that were not quarantined and tested. The local police can't be unaware of such large quantities (of livestock)."
From January 1 to March 10, District 12's Animal Heath Station destroyed nearly 1,300 chickens, 250 kilograms of chicken meat and 4,000 eggs following inspections, according to Huong.
The two H5N1-related deaths this year has taken avian flu fatalities in the country to 59 since 2003.