Is it safe to par-boil chicken legs, (unthawed), then finish cooking them later? I boiled four chicken legs for 25 mins, put them in the fridge then took them back out to finish boiling them four hours later, is this safe?
It is safe, as long as the chicken doesn't stay more than 2 hours in the danger zone (40-140* F / 4-60º C). These 2 hours include preparation, cooking time and storage. 

For further information: Is a partially frozen chicken safe if not immediately cooked at the proper temperature? and Can chicken not completely cooked then cooled be fully cooked later?