How to only scale only the head of a model?

Hi there, I am making baby mobs of a custom mob i am making and i have used the villager code to make the baby mob size smaller as in this snippet. How do i make it that the head of the baby mob larger?

   protected void scale(Villager p_116314_, PoseStack p_116315_, float p_116316_) {
      float f = 0.9375F;
      if (p_116314_.isBaby()) {
         f *= 0.5F;
         this.shadowRadius = 0.25F;
      } else {
         this.shadowRadius = 0.5F;
      }

      p_116315_.scale(f, f, f);
   }