Hi Kim…. if you try adding cocoa powder to your royal icing, I’d love to know how it goes.
If it doesn’t work how you’d like, maybe try adding a dark brown gel paste colour?… although it would lack the chocolate flavour.
I agree with Amanda, you could use dark modelling chocolate, if you want to shape them.
Julez, https://www.facebook.com/pages/Allways-Cakes/450634018350115?ref=hl