The best and safest way to defrost chicken is to leave it in the fridge overnight. Unfortunately, this method is also the slowest and requires advance planning.

The day before you plan to cook your chicken, transfer it from the freezer to the fridge to let it thaw slowly, for at least 24 hours. Keep your meat in it's vacuum-sealed packaging.  Make sure to place the raw chicken in a rimmed container or bowl, ideally at the bottom of your fridge to minimise risk of drips onto your other food as it thaws.

Your chicken still in it's vacuum sealed packaging can actually be quick-thawed in less than 2 hours. 

Fill a large container or the small side of your kitchen sink with cold water and drop your vacuum sealed chicken in. Once thawed, open the packaging, rest the bird and it's ready for cooking.

For Bone In Chickens, the thaw time is significantly reduced because of it's size and cut.