Cookie value cannot be read until I’ve logged into the WP admin

It appears I needed to use an earlier hook. Using the wp or init action hooks allow me to read the cookie’s value without logging into the admin first.

function output_test_cookie() {

if ( isset( $_COOKIE['test-cookie'] ) )
    echo $_COOKIE["test-cookie"];
}
add_action( 'wp', 'output_test_cookie' ); // wp or init is needed