As muddy laborers gawked and a mangy dog growled, a team of 13 U.N. weapons inspectors swooped in on an abandoned farm earlier this month and demanded to enter two long brick buildings with padlocked doors.

The inspectors, a U.N. official said, had received a tip from a Western government that Iraq might have been hiding Scud missiles inside the weather-beaten structures. For the inspectors and, more important, for the U.S. government, the prize was huge: Finding a banned Scud would give the Bush administration the smoking gun it had been desperately seeking, providing clear evidence that Saddam Hussein's government was flouting U.N. Security Council resolutions mandating Iraq's disarmament.

But when the inspectors finally were let inside, after waiting for the better part of a day for the owner to return from a hunting trip, all they found were the remnants of a massive chicken-farming operation. Because the roof was too low and the doors too small, the inspectors concluded that the site likely never was -- and never would be -- a missile silo.

The Jan. 15 visit illustrates how the inspectors have expanded the scope of their activities in recent weeks as they have received more intelligence from the United States and other nations. The inspectors are no longer confining their searches to ammunitions storehouses, chemical plants, missile factories, university laboratories and other sites that have long been connected to the country's weapons programs. Their agenda now is sprinkled with visits to a variety of new and unexpected places, including scientists' homes, abandoned airfields and chicken farms.

But thus far, U.N. officials said, the flow of outside intelligence to the inspectors has not led them to clear evidence that Iraq still possesses -- or is developing -- weapons of mass destruction.

U.S. officials have acknowledged that they are not giving their best intelligence to the inspectors because they fear that sensitive information might be leaked to the Iraqis and that intelligence-gathering sources could be compromised. But U.N. officials who believe that Iraq still has banned weapons have grown increasingly frustrated that the tips they have received are insufficient to find evidence of prohibited arms.

The intelligence, said one U.N. official involved in the inspections, "has not been that great."

"We know the Americans have concerns, but if they want to make their case . . . they should be more forthcoming with us," the official said.

Another U.N. official involved in the inspections accused the United States and other foreign governments of providing "little actionable evidence."

In the most detailed description to date of U.S. intelligence-sharing with the inspectors, Deputy Defense Secretary Paul D. Wolfowitz said last week that the United States has identified the names of Iraqi scientists and sites associated with Iraq's weapons programs that U.S. officials believe could lead the inspectors to uncover evidence of on-going activity to develop banned arms.

"We have provided our analysis of Iraq's nuclear, chemical, biological and missile programs, and we have suggested an inspection strategy and tactics," Wolfowitz said in a speech to the Council on Foreign Relations in New York. "We have provided counterintelligence support to improve the inspectors' ability to thwart Iraqi attempts to penetrate their organizations."

But the information has not always panned out. After almost two months of daily searches, the inspectors have been unable to confirm U.S. and British suspicions -- outlined last year in a CIA report and a British government dossier -- that a host of former weapons sites and industrial facilities have been rebuilt during the past four years to produce banned weapons.

Inspections by the International Atomic Energy Agency have cast doubt on claims by President Bush to the U.N. General Assembly on Sept. 12 that Iraq was seeking to acquire aluminum tubes for use in a secret uranium enrichment program. The aluminum tubes, according to Mohamed ElBaradei, the agency's director general, are consistent with efforts to reverse-engineer rockets. U.N. officials said ElBaradei will present additional evidence to the Security Council today to substantiate that claim.

"Yes, it's possible that we've been misinformed on some things," Wolfowitz said. "But in a country that has a history of constructing Potemkin villages, there's absolutely no way to know whether what the inspectors were shown were, indeed, those aluminum tubes that we're concerned about, or whether it was a whole facade constructed to substantiate a certain story."

U.N. officials declined to identify the country that supplied the information saying that the chicken farm in Dora, a farming community a few miles south of Baghdad, might have been housing Scuds, which are prohibited by the United Nations because their range exceeds 90 miles.

Two days after their visit, the inspectors went to another poultry farm on the outskirts of Baghdad based on an intelligence report that weaponized biological agents might be hidden there. After inspectors scoured the chicken coops and used ground-penetrating radar to determine whether anything was hidden under mounds of drying corn on the farm, they concluded the report was false.

Such visits have clearly amused the Iraqi government, which insists it no longer possesses weapons of mass destruction.

"If we go on a scale of A to D, it's a D," Gen. Amir Saadi, Hussein's chief adviser on weapons issues, said about Western intelligence reports on Iraq. He said the Iraqi government had been "expecting something really big and momentous" after hearing U.S. officials boast about evidence of Iraq's weapons programs.

Asked about the visit to the two chicken farms, Saadi said: "If that's their best, we can't be very worried."

U.S. and U.N. officials said they are concerned that intelligence passed to inspectors may have been leaked to the Iraqi government. A U.N. official has said inspectors believe that Iraqi officials moved materials before inspectors reached at least one site identified in an intelligence report.

U.S. intelligence-sharing may also be limited because Hans Blix, the chief weapons inspector, rebuffed a request by the Bush administration late last year to appoint a senior U.S. official to the U.N. inspection agency to handle the flow of sensitive intelligence. After pressure to step up cooperation, the administration agreed to supply some secret information to the U.N. chief of intelligence, James Corcoran, a former deputy director of the Canadian Security Intelligence Agency who has U.S. intelligence clearances, to test the United Nations' capacity to keep a secret.

The U.S. government also has offered to lend U-2 and Predator spy planes to the inspectors. But Iraq has placed conditions on their use that U.N. officials deem unacceptable, including a demand that U.S. and British warplanes stop entering Iraqi airspace to enforce "no-fly" zones over northern and southern Iraq while the U.N. reconnaissance aircraft are in flight.

U.N. officials say one of the inspectors' biggest successes so far -- the surprise search of an Iraqi scientist's home where they found more than 3,000 pages of sensitive documents, many of them about a uranium enrichment research program -- was the result of an intelligence tip from a foreign government.

"This is definitely a good use of outside information," one senior U.N. official said. "How else are you going to find a house with documents in the middle of Baghdad?"

But apart from that discovery, the official said, "there have not been lots of results."

Lynch reported from the United Nations.

A U.N. weapons inspector walks past a chicken coop that was searched Friday at a farm southwest of Baghdad.