Poultry kept within a one-kilometre radius of major Swiss lakes and rivers must stay indoors from Sunday as part of targeted preventive measures against avian flu.
The restrictions, imposed by the economics ministry, are designed to prevent domestic flocks from coming into contact with migratory birds infected with the H5N1 virus.
The measures will remain in place until April 30 next year and could be reinforced should the need arise. The outdoor ban applies to poultry holdings near around 20 lakes and rivers in low-lying areas.
Thirty-two dead wild birds were found with the H5N1 virus in Switzerland in February and March, mainly around lakes. As a result the Swiss authorities ordered poultry to be locked up from February 20 to May 1. No new cases have been detected in Switzerland since April.
The economics ministry says monitoring of wild birds will continue, especially on lakes Geneva, Constance, Neuchâtel and Zurich where 74 per cent of waterfowl spend the winter.
Switzerland's summertime waterfowl population of 50,000 swells to 500,000 during the winter migration to Africa.
Throughout the winter, samples will be taken from live birds on lakes Constance and Sempach and at the Bolle di Magadino nature reserve in canton Ticino. Similar checks will be carried out on birds shot by hunters on lakes Geneva and Neuchâtel.
As was the case last year, all suspect birds found across Switzerland will be analysed by the authorities.
"The period of vigilance will not be limited to periods of migration, but throughout the winter," said the ministry when it announced the restrictions at the end of last month.
The new measures will affect about 1,000 of the country's 17,000 large poultry farms and 4,000 smaller holdings, say officials.
In addition to the outdoor ban on chickens, ducks, geese and ostriches, poultry markets and exhibitions will be prohibited within the exclusion zone.
Checks will be maintained at the country's borders and all imports from countries affected by bird flu remain banned.
Both the Swiss Farmers Union and Kagfreiland, a farm animal protection organisation, have backed the targeted measures.
Most European Union countries have relaxed restrictions requiring poultry to be kept indoors but say they are ready to act should risk levels increase. Switzerland is not a member of the EU.
The Geneva-based World Health Organization remains on a state of pandemic alert as deaths from the human form of bird flu continue to climb. On Sunday the Indonesian authorities announced that an 11-year-old boy had died from bird flu, raising the national death toll from the disease to 53.
swissinfo with agencies
From October 26 to December 16 last year, Switzerland banned the keeping of domestic poultry outdoors. The aim was to reduce the risk of Swiss animals coming into contact with infected wild birds during the autumn migration period.
A second outdoor ban was imposed from February 20 to May 1 this year after the H5N1 virus was found in wild birds in neighbouring countries during the spring migration.
The latest lock-up list – from October 15 to April 30 next year – affects chickens, hens, turkeys, peacocks, guinea fowl, partridges, pheasants, quails, ducks, geese, ostriches, emus and rheas.
According to the latest WHO update, there have been 253 cases of human bird flu in ten countries since 2003, with 148 deaths.
Most fatalities have occurred when humans have been in close contact with infected poultry.
Health experts fear the H5N1 virus will eventually mutate into a form easily transmissible among humans.
No cases of human bird flu have been reported in Switzerland.