Hello, budgeboy. Each costume has its pros and cons. The Chief Costume causes a lot of damage with its area skill so you can kill the bird using 4 area skills. You are the first one who said this boss is too difficult, maybe you are trying to kill it in a hard way (using the standard costume, for example).
Regarding the wooden boxes on the ship, you need to use the Invisibility Cloak to move through them. There is a potion to recover its mana points before this moment (if you have spent them). Can you print your screen so that I can check if its a bug?