I'm not sure about why Texas, but I do know that you will find more rescues in one are due to puppymills. I never thought of Texas though as a big puppymill area. The states that come to my mind would be Arkansas, Missouri, Kansas, PA and Ohio and I'm sure I've left out a few. Pennsylvania and Ohio are big believe it or not due to Amish. The Amish which because they are such a religous group of people, you would not think, but are the biggest puppymillers. Dutch Country in PA in which they show all the tourist areas and how beautiful fail to show the true side and that is all the barns filled with dogs being bred over and over for profit. These are the Amish. Because puppy auctions are illegal in PA many travel over the line to Ohio and sell at a local flea market (Ran by an Amish man) in which dog auctions are held monthly. This is really the only input I can give. If you are looking for a rescue another great place to check is
www.puppymillrescue.com. They go to these puppy auctions and buy up what they can, then vet them, spay/neuter and place in good homes. The adoption fee is usually $400 or under which considering the price of spay/neuter not to mention shots and vetting is a great deal. Best of luck to you. Elaine (Mom to three rescued Yorkies and one spoiled Morkie)