Chanting “You left me no choice, I have to use my teacher voice!” hundreds of Colorado teachers converged on the state Capitol on Monday to demand changes in school funding and to lobby for higher teacher pay and a stronger retirement fund.

The teachers, who gathered just before noon in the Capitol rotunda, made so much noise that some state representatives and senators left their chambers to watch the rally. A few gave impromptu speeches in support of the teachers, who took a day off work to attend the annual Colorado Education Association’s Lobby Day.

The teachers say lagging salaries and potential cuts to the retirement system will make it impossible for younger educators to remain in the profession for an entire career.

“When I was in school, you knew you weren’t going to get rich,” said Bob Mantooth, a physical education teacher at Kaiser Elementary School in Denver. “You knew you would get a decent salary, and when you were ready to retire you would be OK. For these young teachers, there’s no future. You won’t get people entering into this profession. They don’t want to go into poverty teaching.”

Colorado teachers have joined their peers in Kentucky, Oklahoma, West Virginia and Arizona in staging protests and walk-outs to bring attention to their cause. In Englewood, Monday classes were canceled after more than 150 teachers in that district announced plans to join the rally, and teachers also came from Denver Public Schools and the Boulder Valley School District. The education association reported that about 400 teachers participated.

Teachers who couldn’t make the rally showed their support by carrying signs and walking in large groups into their schools on Monday morning. In the St. Vrain Valley School District, teachers from at least nine schools staged a “walk-in,” the Longmont Times-Call reported.

Scott Silva, an Englewood High School English teacher, said he and his colleagues had support from the administration because the district is struggling to keep up financially. He recently used a social media fundraising site to buy new books for his literature classes.

Colorado is too wealthy of a state to have underfunded schools, he said. He rattled off statistics from the National Education Association that show Colorado was near the bottom in per-pupil-funding, spending about $2,700 less per student than the national average.

Colorado teachers also are paid less than the national average; the average salary of $46,155 in 2016 ranks 46th among states and Washington D.C., according to the National Education Association.

“It shouldn’t be this way in a state like Colorado where there’s a budget surplus,” Silva said. “Let’s start taking care of the kids a little bit.”

The teachers lined out the door Monday afternoon to attend a House Finance Committee hearing on Senate Bill 200, which would cut public employee retirement benefits to shore up PERA, the state retirement plan.

The education association opposes raising the retirement age to 65, wants to limit contributions from current educators and to ensure adequate cost-of-living adjustments are built in.

The committee was on track Tuesday evening to consider proposed amendments — supported by the teachers’ lobby — that would result in a compromise between the current system and measures in the Senate bill. Any changes would force the bill back to the Republican-controlled Senate for approval.

Callie Gonyea, who is in her second year of teaching at Ellis Elementary School in Denver, said she wants to be a teacher for her entire career. But she needs a salary that keeps pace with the cost of living and a solid retirement plan.

“We do it because we love our students,” Gonyea said. “We love to see them grow. The light bulb moments — that’s why we do it.”

For legislators who took time to speak with teachers, the reception was friendly. Tiffany Boyd and Rebecca Lavendore, who teach at Louisville Elementary School in the Boulder Valley, were on their way to thank a Republican senator who recognized PERA was a bipartisan issue and was supporting some of the education association’s recommendations.

Colorado’s teachers do not collect Social Security upon retirement, and, for many, they do not earn enough money to invest in other retirement plans such as IRAs, Lavendore said.

“PERA is it for us,” Boyd said. “It needs to be viable and make people want to stay in teaching.”

The state currently underfunds its schools by $822 million annually, and the shortage hits rural schools especially hard. In next year’s budget, lawmakers plan to “buy down” the annual amount owed to schools by $150 million, and boost per pupil spending by 6 percent, the Associated Press reported.

Among other priorities for teachers at the Capitol is a call for legislators to commit to a freeze on corporate tax breaks “until school funding is restored or until per-pupil funding reaches the national average.” Their union says the average Colorado teacher is paying about $650 per out of their own pockets on students’ needs.

The Associated Press contributed to this report.