When dipping in chocolate, work quickly so chocolate does not go out of temper. If out of temper, it will set with gray streaks.

Cornstarch

1 recipe Marshmallow for Piping

1 recipe Tempered Chocolate for Marshmallow Chicks

Royal Icing for Marshmallow Treats

Sift a thin layer of cornstarch onto the bottom of a rimmed baking sheet to cover surface completely. Pipe chicks directly onto cornstarch, and allow to set uncovered for 30 to 45 minutes. Meanwhile, temper the chocolate.
Line a second baking sheet with parchment paper or a Silpat (a French nonstick baking mat). Set aside. Dust fingers with cornstarch, and gently pick up a chick, dusting off any excess cornstarch from its bottom; place in bowl of tempered chocolate. Using a free hand or chocolate-dipping fork, cover chick with chocolate; lift out, and let excess drip back into bowl. Gently place on lined baking sheet; touch up any bare spots with a chocolate-coated finger. Allow to set at least 3 hours. Pipe on royal-icing eyes with a 1/32-inch (#1 Ateco) tip. Store in an airtight container until ready to serve, or up to 2 weeks.