As far as I understand how mechanics works, there is a hidden parameter of maturing for each non-mature animal.
Just like a trees, newborn animal being slaughtered will produce lower quality goods, and lower quantity as well, and vice versa butchering animals who has least time left to be mature will produce a lot bigger amount of goods.
This leads players to do illogical actions: to guess when to slaughter an animal to receive maximum quality sucklings maw, or waiting pigs full growth to get maximum amount of meat or other product quality. They also hard to predict when it will become adult to plan next breeding, and so on.
Let us know the value of maturing meter, this will help a lot with husbandry, which is very complicated already.