Final answer:
The private solution to the pollution externality was the campaign organized by the nonprofit environmental organization, which aimed to address the negative impacts of the chicken farm's waste disposal.
Step-by-step explanation:
In the scenario provided, the private solution to the externality of pollution was the fundraising campaign organized by the nonprofit environmental organization. This initiative represents a private effort to address the negative externalities caused by the chicken farm's waste disposal. The scenario does not mention any voluntary actions on the part of the chicken farm, nor any government interventions such as fines or regulations. Instead, it showcases how a community-driven organization took steps to rectify the external costs imposed on society by the farm’s pollution. This type of solution is essential in situations where there might not be adequate governmental structures or regulations to handle such pollution issues.