Given that it's a democratically elected government that made the regulation I don't think there is anything the "people who'd rather pay less for cruelly-treat

Given that it's a democratically elected government that made the regulation I don't think there is anything the "people who'd rather pay less for cruelly-treated chickens" can do here other than try to lobby for the rule to be reverted or moving somewhere where animals can be treated "cruelly" without repercussions. It's not always only a question of free market.