from the AWN article:
The Hunger Games is the latest movie phenomenon, judging by its killer box office results and wide demo appeal. But even though it contains 1,200 VFX shots (achieved in a mere 23 weeks and costing far less than the usual tentpole), you wouldn't know it. It's not a VFX-intensive project. Rather, the dystopian, Orwellian nightmare is more reality TV than superhero movie. As a result, director Gary Ross focuses primarily on Katniss' POV with a gritty, verite visual style. The VFX definitely served this plan without trying to call attention to the work.
However, the work is impressively spread around more than a dozen companies across the globe (including Hybride, Rising Sun Pictures, Pixomondo, ILM, Rhythm & Hues, Whiskytree, Digiscope, Clearcut FX) along with technical previs by The Third Floor, previs by Halon and postvis by Proof.
Indeed, VFX onset supervisor Sheena Duggal admits it was a tremendous collaborative effort in which sequences and assets were shared. So you had ILM (supervised by Scott Farrar) and Pixomondo (co-supervised by John Parenteau and Bjorn Mayer) sharing the exterior train and hovercraft sequences. With ILM having just done the Super 8 train work, this came in handy.
And you also had Rising Sun and Rhythm & Hues sharing the animation of the genetically-engineered mutts. Rising Sun gave Rhythm & Hues their basic assets for muscle deformation and fur and color and lighting and Rhythm & Hues took that into their own proprietary system, Voodoo, and skinned it and put muscles onto it and then rigged and animated it and then conducted the asset and gave it back to Rising Sun.