Ecological speculations: The gallusaur presumably lives much like a turkey, but with a carnivorous side and a poorer flying ability. Probably living in groups due to its small size, it likely forages around for beetles, centipedes, and other arthropods, as well as other small food sources. It could be omnivorous, although real compsognathids are thought to have been purely carnivorous. It likely scavenges as well.
In reality feather evolution is thought to have gone through various stages as discussed here and here, starting with a simple "dinofuzz" similar to fur or down, and later evolving into something more like modern bird feathers with a central shaft and barbs coming off from it. The Gallusaur appears to have wings suggesting feathers with a central shaft, but this is probably unrealistic in a compsognathid, as only Dromaeosaurs ("raptors") like Sinornithosaurus have been found with these types of feathers. The two feathered compsognathids that have been found, Sinosauropteryx and Sinocalliopteryx, only had the "dinofuzz" type with no extended feathers on their arms.
Also, in reality compsognathids were probably extinct by the time of Terra Nova, since none have been found past the Albian age which ended about 100 million years ago. One of the last known compsognathids was Mirischia, from South America.