Wild bird trade - inc smuggling - is a means of spreading H5N1, albeit not as massively important as poultry industry. (Reflected partly in a few cases of dead birds with h5n1 in Hong Kong urban areas, inc v near main bird market.)
Also can involve horrible cruelty.

This from Russia:

Russian authorities have given lethal injections to dozens of budgerigars found near the border with Kazakhstan because of fears of the bird flu virus, a state veterinary official told AFP on Thursday.

Russian border guards in the southern Orenburg region found large plastic bags near a railway track containing 397 budgerigars crammed into four cages, said Mikhail Maslov, from the local branch of the state veterinary service.

"Every cage contained a hundred or so birds. Half of them were already dead from the cold. They were apparently thrown from the... train by traffickers," Maslov said.
Lethal injection for budgerigars