Sniffer egg faces aren't culled when covered by blocks

The Bug:

Sniffer egg faces aren't culled when covered by blocks.

Steps to Reproduce:

1. Place down two sniffers eggs on top of one another.
2. Switch to spectator mode and observe the inside faces of the sniffer eggs.
3. Take note as to whether or not sniffer egg faces are culled when covered by blocks.

Observed Behavior:

Sniffer egg faces aren't culled when covered by blocks.

Expected Behavior:

Sniffer egg faces would be culled when covered by blocks.