Her feathers are darker at this point, but unless we come across anypony who is an expert on crows or birds we should be fine for a while longer, at this rate it will become noticeable to everypony within a few months, so I need to find a way to hide her changes, but that's an entirely different problem, my best bet is an illusion spell, but I need it to last several hours, or always be active, and anypony would notice Entropy holding a gem.