According to Professor Jennifer Kwinlan from the Drexel University, when you buy a frozen chicken, it already has salmonella or Campylobacter or even both. These two bacteria are the main reason for food contamination.
Usually, people tend to wash frozen chicken in order to wash visible dirt, to clean it from potential bacteria, etc. Nonetheless, by washing the chicken, the bacteria actually spread on the sink and the surrounding area through the process of aerosolization. Therefore, there is no of exposing yourself to this risk, as the cooking at high temperature will destroy all bacteria.
The safest way to remove any visible dirt is with a paper towel. Just wipe the chicken with a paper towel and then dispose of it.
Statistically speaking, in Great Britain, yearly, around 280000 people are diagnosed with contamination caused by the Campylobacter and most of the contamination occurs due to washing frozen chicken.