cakephp checkbox default
cakephp version 2.3.4で確認
$options = array( 0 => '00000', 1 => '11111', 2 => '22222');
$default = array(0, 2); // $optionsのkeyを指定
echo $this->Form->input('sample', array(
'multiple' => 'checkbox',
'options' => $options,
'default' => $default
));