VERDICT: PLAUSIBLE:
The new incubation strategies explored by oviraptorids and troodontids required the eggs to be partially exposed at the surface, leaving them visible for the first time in dinosaur evolution. The appearance of colored eggs coincides with the evolution of these partially open nests, and so may have been driven by new selective pressures. Brown speckled eggs, for example, may have been better camouflaged from predators when the parents left the nest to feed.
The advantage of baby blue eggs is a bit more uncertain. Some modern birds use egg colors to help fight brood parasites such as cuckoos, by making any imposter eggs more obvious so that they can be discarded by the parents. For now, we can only speculate as to the existence of dinosaur brood parasites, but the idea of a furtive oviraptorid sneaking an egg into another dinosaur’s nest is satisfying to ponder.