Tommo on Twitter: "Trying to make boats have two riders is a walk though the most arcane code, but maybe, maybe it will work :)"

Alternative solution:

                                
1. Take two chicks.                      =>
2. Bring one chick back.           <-        
3. Take two chicks.                      =>  
4. Bring one chick back.           <-        
5. Take one wolf, one chick.             =>  
6. Bring one chick back.           <-        
7. Take one wolf, one chick.             =>  
8. Bring one chick back.           <-        
9. Take one wolf, one chick.             =>  
                                             

/r/Minecraft Thread Link - twitter.com