Vegan activists took part in midnight stealth missions, issued extortion-like demands involving live animals and chained themselves to abattoir equipment, a Queensland court has heard.

Eight activists were each fined between $400 and $600 on Thursday after pleading guilty in Brisbane Magistrates Court to trespassing on agricultural properties last month.

None of their convictions were recorded.

Melissa Joan Donald called police just after midnight on April 13 from a farm near Toowoomba complaining she was being chased by a farmer on quad bike who was shooting at her.