True, chickens can put you in danger of food poisoning, especially if you have unclean chickens.  Corporate chickens bought in the grocery store cannot be trusted.  I know firsthand that factory-raised chickens often come from filthy and unhealthy conditions.  Chickens are not inherently unsafe.  They must contract the bacteria in their lifetime.   If you can find a local farmer who raises clean healthy chickens, you don't have to worry so much about bacteria.

Proper use of meat thermometers enables you wait until the chicken is fully cooked, whether started frozen or thawed.  I use two meat thermometers of different brands and check multiple locations in the chicken.  Again, slow cooking a frozen chicken as described by "Rob" above is the best way to ensure that it's fully thawed and cooked without overcooking the outside or under cooking the inside.

Happy cooking!