So the chickens have 1 beak and 2 legs and the sheep have 4 legs.
So since there are 8 chickens we know that there are 8 beaks
If we multiply 2 legs times 8 chickens we get 16
If we multiply 4 legs times 14 sheep we get 56
The number of legs is 16+56=72
So we have 8 beaks and 72 legs or 8:72
Divide both sides by 8 to simplify and you get 1:9 as the answer