Small birds such as the poussins used here are perfect for barbecuing or grilling. To make them the same thickness throughout so that they cook quickly and evenly, the backbone is removed, then the birds are flattened and secured with metal skewers - called en crapaudine in French.
Tuck under the wings and remove the wishbone. Turn the bird over, cut along each side of the backbone with poultry shears and remove it.
Push down on the bird to break the breastbone, flattening it against the cutting board.
Keeping the bird flat, push a metal skewer through the wings and breast. Push another metal skewer through the thighs.