This is a hard boiled chicken egg painted with colored dyes.”
A brightly-painted chicken egg, hard boiled. It is nothing but a novelty item and has no actual use. According to Chris Avellone, then at Black Isle Studios, the Easter egg was however supposed to hatch a recruitable non-player character named "The Chicken".
In the New Reno Arms basement. The Easter egg is in a pot hidden amongst a pile of crates, near the bottom left corner of the room.