Puzzled when her 29-year-old retarded daughter shrank from her embrace, Gladys Marshall lifted Juanita's shirt and gasped. The young woman's back was a bloody mass of bites, bruises and scratches.

"My daughter is the most precious thing in the world to me," said Marshall.

"And she's been abused so badly. Her skin's been bitten and she's been scratched to pieces. I can't stand seeing her go through this."

Juanita Marshall is a resident of Great Oaks, one of Maryland's newest and most progressive state-run institutions for the mentally retarded.

Built in 1971 as a model facility for the mildly retarded, Great Oaks -- located on Cherry Hill Road in Silver Spring -- soon found its 470 beds filled with severely disabled patients who came pouring out of the state's older, overcrowded insitutions.

Along with those patients came problems.

The major problem, officials say, is a shortage of trained staff members that results in many of the adult residents being left idle. Bored and frustrated, they have began to turn on each other.

According to accident reports filed by staff members, 308 residents were injured in a four-month period last year. Approximately one-fourth of those injuries are listed as "unexplained."

"I'd be arrested if I treated an animal the way my daughter is treated at Great Oaks," said one parent.

Of the state's estimated 90,000 retarded citizens, 2.600 are currently institutionalized. Great Oaks, the second largest facility, is the most overcrowded of Maryland's nine insitutions for the mentally retarded. The largest insitition is rosewood, built in 1827 near Baltimore, which houses 1,200 residents.

Great Oaks administrator Cliff Lockyer and state health administrators acknowledge the insitution's shortcomings. The chief problem, they say, is lack of funds to hire enough competent staff members to care for the clients, especially those with severe psychiatric problems.

"pick me up and diaper me," said Lockyer. "That's what I'm asking people to do for less than $10,00 a year."

Last winter, a 19-year-old maintenance worker was found in a bathroom with a retarded young woman who could neither walk, talk nor feed herself. The man subsequently pleaded guilty in court to forced sexual contact with a mentally incapable person.

One Great Oaks resident was so heavily sedated, according to her father, she was like a "zombia." The woman was transferred to another unit where she was severely beaten by a fellow resident, her father said.

As a result of complaints filed by the Marshalls and other parents of Great Oaks residents, the state's attorney's office and a nonprofit state legal organization for the handicapped are investigating the institution, which one advocate for the mentally retarded called "dangerous."

"I'd rather take a beating myself than have Juanita go through that," said Paul Marshall, who regularly finds his daughter suffering from injuries inflicted by other Great Oaks residents.

But the Marshalls -- like other couples cannot afford to send their daughter to a private facility, where care can cost thousands of dollars a year. Great Oaks, its red brick cottages and modern buildings clustered on 160 wooded acres, charges a maximum of $90 a month based on a family's income.

Great Oaks is not without its success stories, however. According to Lockyer, the facility has placed 39 people in group homes, returned 71 to their families and placed 42 in foster homes.

"Our goal is to get out of Great Oaks those who don't require an institutional setting," he said.

Tom and Gladys Camp say their 25-year-old son behaved "like an animal in the private $800-a-month insitution where he lived before coming to Great Oaks.

"He can now feed himself and go to the bathroom by himself," said Tom Camp. "He's been patiently taught."

Many of the residents at Great Oaks cannot talk, eat or use the bathroom facilities by themselves. Severely deformed with oversized heads and atrophied limbs, more than half of the patients cannot say where they hurt or who is hurting them.

They eat cockroaches, birds, clothing or anything they find, according to employes. Most of the rooms are bare. There are few, if any toys to play with.

Ironically, Great Oaks was hailed by state officials 10 years ago as a vast improvement over the "warehouses" of the past. But cottages where mildly retarded residents were to live semi-independent lives are now boarded-up. Inside, severely retarded residents who are prone to violence pace like caged animals, scream, pound their heads against cinderblock walls and smear the own feces on the floors, staff-members say.

But in another cottage, a group of mildly retarded women finish supper, clear the tables and file into the living room to watch television. One resident excitedly packs her records in anticipation of moving to a group home in Wheaton.

"They thought Great Oaks was a great step forward, but it just missed," said Carl Storm of the Maryland Association for Retarded Citizens.

A small but growing number of retarded citizens live in community-run group homes funded by state, federal and private grants.

Although Great Oaks provides training for some of the residents and buses other to small workshops in the commuity, many adults, Lockyer said, "are getting zero."

"It's a lack of programs that produces abnormal activity," said Frand J. Menolascino, a psychiatrist on the President's Council on Mental Retardation. "If there is no program, the person withdraws into himself with behavior like skin-picking and head rocking. You have to find out what prompts abuse and what doesn't."

Lockyer points to the problems of programming for patients, who range from toddlers breathing through tubes to 70-year-old patients with the mental abilities of infants.

"You're asking us to cover a full range of people 24-hours-a-day with a limited staff and we just can't," said Lockyer.

When federal laws mandated education for handicapped school-age children, Lockyer said, the institution focused its attention on that age group.

"We 've come off with a fine program for school-aged children," Lockyer said. "My goal now is to strive for an equally excellent adult program."

To this end, the facility has requested $415,000 from the state this year for 40 more staff positions, including activity therapists and psychologists.

"Great Oaks' budget provides a minimal, direct-care staff," said Ted Lukas of the state Department of Health and Mental Hygiene. "Yes, they need additional funds. Yes, the state knows and we are doing everything possible to bring the staff-patient ratio into line."

Currently, there are approximately 250 direct-care workers supervising 458 patients over a 24-hour period. Because of low payand morale, officials say there is a high absentee rate among staffers.

Often, as many as 30 hyperactive retarded men are left in a bare cinderblock compound for hours with only one supervisor.

The staff member, parents have complained, is often a teen-ager with a high school degree and two weeks of orientation training at Great Oaks.

"Getting high is the best part of my day," said one employ, who claimed that drug use was common among some of hte staff. "It helps me deal with the fact that I don't have anyone to help me."

The employe watched 20 men pace around the room or listlessly gaze up at a television mounted high on the wall. Pointing to a young man who was playing with a set of plastic blocks, the employe said, "He only has those because I stole them for him."

Two young women staffers said they regularly spend their own money providing residents with evening activities on the weekend.

"We call it 'Saturday Night Live one of the workers said. "We do it for our sanity as well as theirs."

A former worker recalled, "I was sometimes afraid of those kids but I didn't want to show it. I did't want to show them anything but love."

She was suspended from Great Oaks last year for refusing to watch two separate groups of residents one night. "I can't be in two places at once," she said. "I was afraid one of the kids would have a seizure and die and I would be blamed."

Another woman quit last summer after she was assigned to watch a roomful of retarded men at midnight, her third day at Great Oaks.

She said the men were not toilet trained. In her written report, she said that while attending to several of the men in the bathroom, a male patient in the next room was raping another resident, who was banging his head on the wall in terror.

"There wasn't anything I could do," she recalled.

Union representatives for the American Federation of State, County and Municipal Employees receive nearly 30 phone calls each month from Great Oaks' staffers.

"They work under terrible conditions." said union official Dan Bolandor.

Critics argue that providing more money for Great Oaks isn't the solution.

"The dilemma for us is that we don't want more money going into Great Oaks," said Curtis Decker of the Maryland Advocacy Unit for the Developmentally Disabled. "Money should be spent so people can be brought out of Great Oaks."