Fairfax County dog owners would have to leash their animals during neighborhood strolls if the Board of Supervisors passes the tough new laws it is considering.

Leashing would be required when the dog is taken beyond its owner's property.

Only three of 11 speakers at a public hearing Monday on proposed amendments to the animal control ordinance were critical of the leashing measure and other provisions.

"I was amazed," said Richard Amity, director of the Fairfax County department of animal control. "I expected a lot more reaction to the leash law."

While most of the supervisors appeared to support the thrust of the provisions, some of them had reservations about specifics.

"I'm sure it will cause a lot of heartburn," Supervisor Marie B. Travesky (R-Springfield) said after the hearing. "A lot of people don't know about it yet."

Some of the speakers at the hearing represented groups that helped to draft the proposed legislation.

Besides requiring leashing, the amendments would:

Prohibit the keeping of wild animals, many of which are now owned by county residents and sold at county pet stores. There is no "grandfather" provision in the proposed legislation that would permit present pet monkeys and other wild animals to be kept by their owners.

Set stiff standards for animal cruelty and give the county the power to enforce them through an expanded staff of animal wardens. Under this provision animals could not be carried in a vehicle in "an unhumane manner," chickens or ducklings under eight weeks of age could not be sold as pets, and no live animal, reptile or bird could be offered as a prize in games, contests or business agreements.

Require licenses be worn by dogs (as a tag).

Give the department of animal control the authority "to summarily destroy" animals it feels are injured beyond medical help or are a contagion threat.

However, the proposals would allow fish, reptiles and nonpoisonous snakes to be sold.

The penalties proposed vary. For keeping a wild animal, one could be fined up to $500. For violating the leash law, one could be fined $5 to $25, and for inflicting cruelty the penalty would be a fine of up to $1,000, 12 months in jail, or both.

The supervisors are expected to make a decision on the proposals in two weeks, after they receive recommendations from the county staff.

The proposals were made partly generated because of mounting citizen complaints of animals being mistreated or of dogs running at will through neighborhoods, Amity and some of the supervisors said.

Mary Eleanor Brademan, chairman of the Virginia Citizens Committee for the Elimination of Animal Abuse and an official of the Washington Humane Society, told of one case where the owners of a dog and its puppies went on a four-day trip during a rainstorm and left the animals in a penned area without food. According to Mrs. Brademan the mother dug holes for her puppies as they died of starvation.

The ban against exotic animals would outlaw the sale of many animals that can be bought at pet stores throughout the county.

Amity contended that the ban is entirely reasonable.

"Who, for example, would want a monkey?" he asked in an interview. "They stink; they're filthy. They will throw their feces at you."

One of the few speakers who argued against the proposals were county resident Mary Olds, who told the supervisors:

"Part of the amendments are probably unenforceable as written since there is not a 'grandfather' clause . . . Please consider the rights of my skunk as well as the rights of myself and my husband."

According to Amity and other animal welfare people, the ban on keeping exotic animals was prompted because monkeys and other imported animals often lose their appeal after they are kept for a short period in homes thousands of miles from their habitats. These officials said that the owners, in desperation, often take the animals to shelters and refuges, passing the already strained ability of these places to care for stray and injured animals.