The brood planet was a world in deep space used by the Chimerons to raise their young. (TV: Delta and the Bannermen) The surface was covered in hexagonal cells that were big enough to hold a full-grown Chimeron.
After defeating the Bannermen, Delta the Chimeron Queen, along with former human Billy, reached the brood planet with the Chimeron princess. After a few years, Delta said she would be able to reproduce the nucleus of an entire community, after which they could return to Chumeria and repopulate it completely. (PROSE: Delta and the Bannermen)