Yep it is quite difficult to find much in the pet stores that isn't foreign sourced. I feed my girls freeze dried green beef tripe from a company called Dinovite. Great people based in Kentucky and with great products,I can't say enough good things about them. Just do a web search on Dinovite and you will find the web site or you could just add a .com after their name.
Kirbdog
Sorry about the double post.