Idle Animation Doesnt Switch Properly

Using the roblox default animation script and 3 custom animations made (Idle1, Idle2, Idle3). Idle animation1 works fine except that it doesnt randomly activate Idle2 or Idle3, whenever it reaches the end of its looped track. Idle2 and Idle3 whenever the tracks end Idle1 doesnt play at all. If someone can let me know why this happens it would be greatly appreciated, whenever I use the roblox catalog animations it works completely fine