It was hard to tell this week which activities at the National Zoo the youngsters liked best: petting the miniature donkeys, watching cows get a bath or cavorting on a giant rubberized pizza with movable mushrooms.

Cows and playground equipment at the zoo?

These and other novelties are part of the $5 million Kids' Farm that opens officially today at 11 a.m. The nearly two-acre expanse, at the end of the zoo near the Picnic Pavilion and Parking Lot D, is designed to teach children about farm animals, including grooming and feeding.

"It's been a big project in the making," said Bob King, assistant curator for small mammals, who oversaw preparations for the exhibit. "It's almost a storybook farm or a Fisher-Price rendition of what a barnyard should look like."

In addition to cows and miniature donkeys, the farm features two breeds of goats, six breeds of chickens and a pond with a small flock of colorful ducks. Visitors can view the animals in a pasture, a bright red barn and special enclosures. Interactive graphics and quizzes provide information about the animals and their care.

For the first time at the zoo, children will have a chance to touch some of the animals.

"The kids here are so urban, they only know these animals from picture books," said David Philhower, founding teacher at Capital City Public Charter School. His delighted third- and fourth-graders were among those given a special preview of the new exhibit on Thursday.

In recent years, an increasing number of zoos have been adding areas, most of them barnyards, where children can have contact with animals. According to the American Zoo and Aquarium Association, nearly 70 percent of its 163 member zoos have or will soon open "petting zoos" featuring goats, sheep, cows and occasionally chickens.

The impetus for Kids' Farm began several years ago when Rep. Ralph Regula (R-Ohio), who owns a working farm, decided that urban youths should "know where food comes from." A Smithsonian Institution regent who has helped increase the zoo's budget, Regula earmarked funds for the project.

Some zoo officials were skeptical initially, believing farm animals were more suited to a county fair. Michael Robinson, then the zoo's director, wanted to expand the educational component by including graphics on how farm animals and crops helped build and stabilize civilizations. That idea got dropped after Robinson left in 2000.

Under Lucy H. Spelman, the current director, the zoo has played down the "petting zoo" aspect of the exhibit. Instead, the emphasis is on educating visitors about several farm animals. The yard where the public can touch the animals is called the Caring Corral.

Construction of Kids' Farm began in April 2003. The species on display were selected because of their gentle dispositions. Except for two goats, all the animals come from farms in Maryland.

"It's all about animal care," said Susan Ades, the zoo's acting head of exhibition planning and design. "Visitors will be helping in brushing the donkeys, giving water and shoveling poop -- that's an important part of animal care."

With the addition of a petting area, the zoo must adhere to strict federal sanitation guidelines to prevent the spread of diseases. Hand-washing stations have been set up at the Caring Corral's entrance and exit, and there is a kid-friendly graphic illustrating good hygiene. Staff will make sure children don't bring food into the exhibit or try to eat something after touching an animal.

In another zoo first, Kids' Farm has a recreation site for young visitors -- the pizza play area and garden. Youngsters can pick up, crawl through or slide down various vegetarian, rubberized pizza toppings. There is also a real vegetable garden with tomatoes, corn, wheat and thyme, and children will learn how to make pizza sauce and how a cow's milk becomes cheese.

The idea, said zoo spokeswoman Peper Long, is to show youngsters that pizza and other food items don't just land in their lunchboxes. But given the target audience of 3- to 8-year-olds, the zoo has steered clear of discussing how chickens, cows and other farm animals end up on dinner plates.

"We're not describing the whole process," Long said. "It's an educational exhibit, but [it's] not designed to overwhelm."

The zoo has taken precautions to guard against predators and discourage rodents, extending wire fencing into the ground and using rodent-proof screening material. The animals will be out in yards during the day, then brought inside at night.

The zoo also has designed the exhibit to be environmentally friendly, with state-of-the-art water retention ponds to avoid runoff into Rock Creek. Recycled plastic was used to build a boardwalk through the farm.

The complex has 62 animals: 10 mammals and 52 birds, including some, such as Dominique chickens, that can be traced to Colonial times.

Kids' Farm received additional support from Giant Food, which raised $9,400 for the exhibit's public education programs by encouraging shoppers to make $1, $3 or $5 contributions last month while paying for groceries.

The farm will be overseen by staff members, horticulturists and volunteers. More volunteers are needed to answer visitor questions and supervise the Caring Corral. For information, call 202-673-4874 or see the Friends of the National Zoo Web site at