For Cornelis Zwennes the six blue neck Indian peacocks he raised on his seven-acre McLean farm were more than just pretty birds. They were the product of a year of careful breeding.

When a loose huskie broke into his aviary and killed the blue and brown colored peacocks in April, Zwennes was distraught.

Today, Zweenes probably will receive some compensation from Fairfax County for the dead birds. But for the 50-year-old Netherlands-born ornithologist, the issue is larger than the $330 livestock claim he submitted to the Board of Supervisors.

Zwennes is angry that some dog owners are not observing the county's leash law and he wants to see something done about it before his collection of gold, silver and Lady Amherst pheasants, quails and ring-neck doves go the way of his favorite blue necks.

"Having this kind of interest is very difficult because there is no control over the dogs," he laments.

Zwennes, a Connecticut Avenue jeweler, is not only one complaining about loose dogs. Two Irish setters broke into his neighbor's greenhouse last week, killing strangely enough, his two Indian blue necks.

"Being able to enforce the lease law is a real problem," says John H. Smith, chief warden of the department of animal control.

The department receives on average of 50 complaints a day and more than 70 percent involve loose dogs, according to Smith.

State law requires the county to pay claims if the loose dog's owners can't be found. "We've paid for rabbits, chickens, goats and ducks," says Smith, adding that in the last few yea rs the animal warden have met with greater success in catching the guilty dogs and tracing their owners.

Although the game wardens answered Zwennes' call immediately, they arrived to find only the dog tracks left imprinted in the mud around the aviary.

The wardens picked up two loose huskies the following day but couldn't pin the crime on them. Smith says that if a dog is caught soon after an incident, blood stains will prove his guilt. Otherwise, the county is left to pick up the tab.

Zwennes isn't sure whether he will replace the blue necks, considered among the most colorful peacocks. But he is certain that he will have to keep a closer watch on his birds in the future.

Only last week he discovered one of his silver peacocks dead from a dog attack. "You have to have four or five acres for peacocks -- they like to roam and I'm not going to stop letting them," Zwennes says.