According to this story, the Alabama Secretary of State published guidelines for write-in votes recently. The guidelines surprisingly say that if the total number of write-ins is greater than the margin between the candidates who place first and second, they will all be counted.
Alabama doesn’t have any procedure for write-in candidates to file to have their write-ins counted. In the past the counties have mostly counted all write-ins, but the state has not tallied them, so there is never an official statewide total for a write-in candidate running for an office that is statewide or which extends beyond one county.