I hunt 4 dogs at a time and that's all, a lacy, red cur,a cat or hound depending on where I hunt, and my tank. They are all to big to get through the brush.
I've never hunted South Texas, or where you hunt, but Lacys are not big dogs by their standards. Are you sure your dogs are worth feeding if they can't get it done?
I'm not hammering on you or being a smarta$$, just a question to make you step back and re-analyze your dogs and the standards you hold for em, and stop making excuses for them.