Both Dellen Millard, 28, and Mark Smich, 26, appeared via video link in a Hamilton courtroom today.
Millard and Smich, who are both charged with first-degree murder in connection to Bosma's death, said little during their brief appearances.
Millard stood with his hands clasped in front of him and said only his name. Smich did the same. Both wore jail-issue orange jumpsuits.
The pretrial is a hearing to try to resolve legal issues ahead of time and to map out a plan for the trial.
Bosma's widow, Sharlene, was in the courtroom Thursday, flanked by family members. She stared at the screen intently when each accused was shown, but declined an interview after the proceedings.
Det. Sgt Matt Kavanagh of Hamilton police was also in court, but declined to speak, saying he couldn't with court proceedings underway.
Toronto police officers have been searching Millard's Waterloo Region farm this week as they investigate the disappearance of Toronto woman Laura Babcock.
Officers have been seen jotting notes, shooting photographs and collecting evidence as they continue to search the North Dumfries farm.
About a half dozen officers from the forensics and homicide departments streamed in and out of a barn on the property Thursday to work under the glow of a portable lamp powered by a gas generator, which could be heard rumbling from Roseville Road.
Burned human remains were previously located on the farm, and investigators said they were confident they belong to Bosma, who disappeared from his Ancaster home after he went on a test drive in his truck on May 6 with two strangers who responded to an online ad.
Forensics and homicide officers wearing protective white suits were seen in front of the main barn at the property on Wednesday. At the back of the barn, police have set up a large blue tent, in the same area where they started taking hay out of the barn on Tuesday.
A stained plank of wood was also removed from the barn.
Babcock, 23, had a relationship with Millard, police have said, and was reported missing in June 2012. Babcock's cellphone records show Millard was one of the last people she called before she went missing.