Zombie AI Lag when checking if it should jump

Hello, I have made a very simple Zombie AI script, but i am having trouble with jumping. The current code i have works fine, but the second i have 3+ zombies jumping, unity lags extreamly bad, is there a way to stop this? is it just because i am calculating to many collisions? this is my code:

 var Player : GameObject;
 var Waypoint : Vector3 = Vector3.zero;
 var inMob : boolean = false;
 var isLeader : boolean = false;
 var rotSpeed : float = 1;
 var SpottingDistance : float = 10;
 var Dis : float = 100;
 var motor : CharacterMotor;
 private var controller : CharacterController;
  var AttackPlayer : boolean = false;
 function Start(){
  Player = GameObject.FindWithTag("Player");
  controller = GetComponent(CharacterController);
  motor = GetComponent(CharacterMotor);
 }
 
 function FixedUpdate(){
 
  if (!AttackPlayer){
     
  if (Vector2.Distance(Vector2(transform.position.x,transform.position.z),Vector2(Waypoint.x,Waypoint.z)) < 15){
  AssignWaypoint(Vector3.zero);
  }else{
  var WaypointDirection = Waypoint - transform.position;
  //controller.SimpleMove(WaypointDirection);
  
  motor.inputMoveDirection = Vector3.ClampMagnitude(WaypointDirection,1);//transform.rotation * WaypointDirection;
  }
  }else{
  
  
  var PlayerDirection = Player.transform.position - transform.position;
  //controller.SimpleMove(WaypointDirection);
  
  motor.inputMoveDirection = Vector3.ClampMagnitude(PlayerDirection,1);//transform.rotation * WaypointDirection;
  }
 
 
 
 var loc : Vector3 = Waypoint;
 var PlayerDirectionFixed = Player.transform.position - Vector3(0,0.5,0) - transform.position;
 var Yofset : float = 1.5;
 
 
  Dis = Vector3.Distance(Vector2(Player.transform.position.x,Player.transform.position.z),Vector2(transform.position.x, transform.position.z));
      if (Dis < SpottingDistance){
       if (Dis < 16)
       Yofset = 1;
       
       if (Dis < 5.8)
       Yofset = 1;
       
       
       
       
       AttackPlayer = true;// Incase the ray doesn't work
       var hit : RaycastHit;
      if (Physics.Raycast (transform.position + Vector3(0,Yofset,0), PlayerDirectionFixed, hit, SpottingDistance+2)){//Ignore the player
      if (hit.transform.tag != "Player" && hit.transform.tag != "MainCamera" && hit.transform.tag != "IgnoreRay"){
      AttackPlayer = false;
      
      
      Debug.DrawRay (transform.position + Vector3(0,Yofset,0), PlayerDirectionFixed, Color.red);  
      }else{
      AttackPlayer = true;
          Debug.DrawRay (transform.position + Vector3(0,Yofset,0), PlayerDirectionFixed, Color.green);  
      }       
      }else{
          AttackPlayer = true;
          Debug.DrawRay (transform.position + Vector3(0,Yofset,0), PlayerDirectionFixed, Color.green);         
          }
      }else{
       AttackPlayer = false;
      }
      
     if (AttackPlayer)
      loc = Player.transform.position;
      
    // if (AttackPlayer)
    // Waypoint = Player.transform.position;//to come back the 'I have better waypoints to go to' glich
     
     
      
     var targetRotation = Quaternion.LookRotation (loc - transform.position, Vector3.up);
  transform.rotation = Quaternion.Slerp(transform.rotation, targetRotation, Time.deltaTime * 2.0);
  transform.rotation.x = 0; transform.rotation.z = 0; // rotating it towards the target/waypoint
  
    
 }
 
 function AssignWaypoint(location : Vector3){
  if (location != Vector3.zero){
  Waypoint = location;
  }else{
  var Rnd : Vector3 = Vector3.zero;
  Rnd.x = Random.Range(-300,300);
  Rnd.z = Random.Range(-300,300);
  Rnd.y = 0;
  Waypoint = Rnd;
  }
 }
 
 function OnControllerColliderHit (hit : ControllerColliderHit) {
 
    
 if (hit.moveDirection != Vector3.zero && hit.moveDirection.y == 0){
  //var wallHit : RaycastHit;
     // if (Physics.Raycast (transform.position + transform.forward, transform.forward, wallHit, 3)){//Ignore the player
     // if (wallHit.transform.gameObject == null){
     // 
     // Debug.DrawRay (transform.position + transform.forward, transform.forward, Color.blue);  //add jump here
     // motor.inputJump = true;
     // 
     // }else{
     // Debug.DrawRay (transform.position + transform.forward, transform.forward, Color.magenta);  
     // motor.inputJump = false;
     // }   
     // 
  // }
  
  Debug.DrawRay (transform.position + transform.forward, transform.forward, Color.blue);  //add jump here
     motor.inputJump = true;
     yield WaitForSeconds(0.5);
    motor.inputJump = false;
     
 }
 }
 
 
 
 @script RequireComponent (CharacterMotor)
 @script AddComponentMenu ("Character/FPS Input Controller")

Tank you in advance, Lachee