Avian colibacillosis — pathogenic Escherichia coli infections — is one of the three biggest infectious disease challenges in poultry production. It costs money, kills birds, and drags down flock performance in ways that are hard to fully account for on a spreadsheet. Regulatory shifts toward single-compound, standardized veterinary drugs changed everything. Where you once could reach for a combination product and cover your bases, now you’re working with a narrower set of tools. If you’ve ever been in a barn with a deteriorating flock, watching a plain amoxicillin product fail to turn things around, you know exactly what that narrowness feels like. The gap isn’t really about the drug being bad. It’s…