antique chocolate moulds, HELP!

A dear friend brought me back some metal antique choccie moulds from OS and now I'd like to use them. They are chickens on a nest (2 pieces with metal clips)but they don't have a hollow to pour the choc in like I've seen on many vids. How the hell do you get the chocolate in both sides and put them together without losing it (literally!) I know I'm missing something really simple here. I thought perhaps they were for hollow chocs and so would have to do one side at a time, but why the clips? HELP!

yours in chocolate

Deborah