If I attach a Rainbow Energy to Shuckle with "Fermenting Liquid" Poke-BODY that has 5 damage counters on it, would it be knocked out prior to its Poke-BODY being applied or would I get to draw the card before it's knocked out?
It is a Poke-BODY that is automatically triggered, so you would get to draw the card.
Source: TPCi Rules Team (2012-03-15)

Relevant cards

Note: All applicable cards may not be listed below.
HSP_HGSS15
HSP_HGSS15