Don't do toggle since you care about the state. Toggle can get you into confusing situations. Instead, on change of a checkbox, see if there are any checked and do the slideDown, else do the slideUp
$(':checkbox').change(function() {
// use the :checked selector to find any that are checked
if ($(':checked').length) {
$('.checkbox-tools').slideDown('slow');
} else {
$('.checkbox-tools').slideUp('slow');
}
});