During the raid Thurgau authorities seized the farm's 300 animals, which included horses, pigs, cows, goats, sheep and even llamas, and took them to a safe place under veterinary supervision, Thurgau police said on Tuesday.
Warning: distressing photo below
The raid was carried out by a special task force put together after photos emerged in newspaper Blick last week of severely malnourished horses.
The photos were taken by a former employee who lodged a criminal complaint against the breeder, claiming that 13 horses had already died of hunger and others were extremely malnourished.
The breeder already had several convictions for animal cruelty, reported Swiss media. However the farm had been subjected to many inspections in recent months and no evidence of mistreatment had been found, Thurgau interior minister Walter Schönholzer, leading the task force, told the press after the raid.
However, authorities decided to act quickly after the photos were authenticated by the prosecutor, proving that the animals were neglected and housed in inadequate conditions, he said.
The breeder was taken into custody and will be investigated under cantonal animal welfare laws on suspicion of mistreating animals. He was also issued with an immediate ban on breeding animals.
Supporters of animal rights demonstrated outside the Hefenhofen farm on Sunday and Monday morning as well as outside a Frauenfeld building housing the cantonal authorities, urging them to act, reported Blick.
They were protesting at what they saw as the authorities' inaction over several years, when the breeder's alleged mistreatment of animals was widely suspected in the community.