Norman McConnachie, 42, and Rachel Boyd, 39, both of Newtonhill, are accused of wilfully ill-treating two school girls in a manner likely to cause unnecessary suffering or injury.
The pair are accused of forcing the teenagers to exercise outdoors in snow and dragging them through dog excrement and urine.
One of the girls told the trial at Aberdeen Sheriff Court that Mr McConnachie instructed her to go into the kitchen of a house after she spilled some juice.
The 17-year-old, who cannot be named, claimed he tipped some food into a dog bowl and told her to eat it.
Mr McConnachie is further accused of sexually assaulting the girls in 2011.
They deny all charges.
The trial continues.