The most effective way to avoid salmonella (other than abstaining from eating poultry) is to know where your food is coming from. When choosing a chicken or a turkey to consume, it is imperative to consider its genetics, the conditions in which it was raised, what it was fed, and whether or not it was treated with antibiotics. Avoiding animals that were bred and raised on a factory farm is a step in the right direction.
While the Humane Society of the United States and others have worked with industry to secure voluntarily agreements to phase out some of the worst confinement systems, there is still no legislation or regulatory oversight. In fact, there are still no federal regulations protecting farm animal welfare.