Kayn is not in the free rotation after 3 weeks of his release

3 weeks have passed since was released. Normally after 3 weeks of a champions release the champion takes a place to the free champion rotation. Despite this fact, I opened my PC to play and then I realised that wasn't in the free rotation! Now I started this discussion to learn why is not in the free rotation like ALL the other champions Riot has released. Why Riot? [zombie-brand-mindblown]