TRENTON, N.J., JULY 21 -- A pricelessporcelain sculpture destroyed during its shipment from a Moscow exhibition back to the White House had been inexplicably routed on three separate flights instead of one, its maker said today.

An official at Boehm Studios said the circuitous route increased the possibility of mishandling and damage.

"We're at a loss to explain why the route was changed. We just don't know why it went the route it went," said Boehm Studios President Frank J. Consentino.

The life-size "Birds of Peace" sculpture, of two swans and two cygnets, was loaned by the White House for a six-week exhibit that featured about 45 porcelain pieces crafted by Boehm Studios in Trenton.

After the show, a Boehm employe carefully packed the figures in special crates for the return trip, Consentino said. But when Boehm officials opened the "Birds of Peace" crate after its arrival, they found the work shattered into scores of pieces.

Consentino said that crate and 17 others carrying the exhibits were supposed to have been trucked from Moscow to Helsinki, then flown directly to Kennedy International Airport in New York.

However, the 17 crates were separated from the "Birds of Peace" crate and were flown from Moscow to Helsinki. Those crates then were shipped by a Finnair jet to New York.

About half the items in the other 17 crates also were damaged.

The "Birds of Peace" crate was flown from Moscow to Frankfurt, West Germany, and then to Helsinki, where it was put on a third jet and sent to New York, he said.

E. Wallace Lawrence, chairman of the Russian Travel Bureau Inc., which helped arrange the shipping, said it was his understanding that Soviet officials, for some unknown reason, insisted on changing the plans.

"The original plan was to go by truck to Helsinki because we were concerned about ... moving it too often," Lawrence said.

"Somebody in Moscow told the Boehm man there that that was not the plan and that the plan was to move it to the Moscow airport and then fly it on Aeroflot to Helsinki, all the pieces.

"Nobody can point a finger at this point, except that if it had gone according to schedule, who knows, there might not have been any damages. We are all upset that the procedures were changed in Moscow, and we don't know who changed them," Lawrence said.

A Finnair official said the damage did not occur while that company handled the crate.

"It didn't happen on Finnair. We know that," said Vinny Pannullo, Finnair's North American cargo service manager.

Consentino said the crate shows signs of being mishandled, but he doesn't believe the Soviets caused the damage. The Soviets were "extremely careful" in handling the shipment when it was sent over, he said.

A woman in the press office at the Soviet Embassy in Washington directed a call seeking comment to a cultural affairs office. Nobody answered the telephone in that office.

The sculpture had been a gift by the Boehm Studios to the White House Historical Society in 1975. It was borrowed from the White House with President Reagan's permission.

Only two other "Birds of Peace" figures were made. One is in Beijing, a gift from former president Richard Nixon. The other is in the Vatican, a gift from an anonymous donor who purchased it for $150,000 in 1976.

The intricate and detailed sculpture took two years to create. Ten tons of plaster were made to create the molds, which were purposely broken after the pieces were made