The US Cooperative Extension System is a non-formal education program based at US land grant universities. It is designed to help people implement research-based knowledge in their lives. State extension services publish high quality, free information on many topics, including agriculture, health, disaster preparedness, energy, family issues, nutrition, landscaping and pest management.
Anyone can search for extension information Google Scholar with "cooperative extension" [your topic]. For example: cooperative extension chicken botulism, This will search cooperative extension publications around the country which mention botulism in chickens. In Google Scholar you can force words to be searched as a phrase in the results by putting them in quotes. You can force a word to be in the results by putting a + in front of it (no space.) For example: "cooperative extension" +chicken +botulism will require the phrase search and the last two words to be in the resulting hits.
Extension documents are a rich and ever-updated source of targeted practical information from across the country. They are not primary or peer reviewed.