As of last fall Blue Buffalo was using Simmons for a cannery. They opened their own kibble manufacturing facility last year; they still use co-packers:
http://www.foodmanufacturing.com/news/2014/08/blue-buffalo-factory-opens-90m-plant-joplin
http://www.petfoodindustry.com/articles/4467-blue-buffalo-opens-heartland-pet-food-manufacturing-facility
Contact them if you want to know who else manufactures their dry foods and where they source their ingredients:
http://bluebuffalo.com/contact/
Check out their website FAQ’s for their statement of where their food is manufactured:
http://bluebuffalo.com/frequently-asked-questions/
