Reducing Weight

Hi folks,

I've been plotting out a rather ambitious costume of a more or less life-size chocobo based on this type of puppet/costume.  I have pretty much all of the mechanics for movement figured out, but it requires the performer to support most, if not all, of the weight of the head and neck.  Between the beak and the size of the head (at least a foot long), I'm not sure if low density foam or resin would make a lighter head.  Suggestions, experiences, etc are more than welcome.