SAN DIEGO -- Most students at Chula Vista Middle School had a substitute teacher on Thursday as 38 of the school's 48 teachers called in sick, 10News reported.

Parent Antonio May arrived at the school office Thursday morning to find out what was going on, and said, "My son sent me a message saying, 'What's going on with the teachers,' because they had too many substitutes. It's not a good thing to do, the teachers; the reason they are sick is not true," said May.

A school spokeswoman said all of the classes were covered by substitutes or resource teachers from the Sweetwater Union High School District office. They'll be docked one day's pay unless they have a doctor's note.

Students at Chula Vista Middle School aren't the only ones affected by the ongoing contract battle between the Sweetwater Union High School District and the union that represents its 1,800 teachers.

On Thursday morning, teachers at the San Ysidro Adult Education Center held a short informational picket that they dubbed a "black parade." They wore black clothing and held signs that read, "I don't want to strike, but I will." Students watched, and some applauded but the union members were not allowed to interact with them during their demonstration. Teachers said the budget problems have hit the adult schools especially hard.

"I don't see other schools losing as much as adult schools. We might be destroyed all together, and that's what worries me," said teacher Adrienne Medina.

The teachers have been without a contract for 15 months, and most said they are most upset about cuts to their benefits and increased class sizes.

"The district has imposed a proposal that was not agreed to by the association, increasing the staffing ratio from 28-1 to 30-1," said Sweetwater Education Association President Alex Anguiano.

The district said teachers still won't go above the cap of 176 contacts a day, which is the agreement under the old contract. The new staffing ratio would save an estimated $5.4 million, and the budget deficit is estimated at more than $11 million.

Anguiano said he realizes the district is dealing with unprecedented economic times, but the students should come first.

"Our working environment is our students learning environment," said Anguiano.

He also said the union does not condone or support the sickout at Chula Vista Middle School.

Sweetwater Union High School District spokeswoman Lillian Leopold said the money simply isn't there.

"We're one of the only districts, I think, in the county that has had no layoffs, no furloughs, no pay cuts and 85 percent of our budget is salaries," said Leopold.

Anguiano said dozens of positions have been eliminated through teachers who have retired.

Both sides will meet with a mediator on October 7, but if an agreement can't be reached a strike vote could happen shortly before Christmas.