Programmatically set value of Boolean radio button field in form
First, check you are setting the #default_value property at a correct level in the $form array. It seems quite weird to get multiple values in $form['profile_company']['field_employees']['und'], so I'm not sure about assigning defaults nested under [0]['value'] (but I could be wrong). 

A good rule is to ensure you set #default_value at the same level as the #options array. For example, if you would have these options under the lang code like :

print_r($form['profile_company']['field_employees']['und']);

# Output :
Array
(
    ['#options'] =&gt; Array (
        # ... =&gt; ...
    ),
    # ... =&gt; ...
);


... you would set the #default_value at the same level : 

$form['profile_company']['field_employees']['und']['#default_value'] = $default_value;




Secondly, ensure the #default_value is mapped to an existing key in the form #options array : 

# Let's say your options are defined as : 
$form['profile_company']['field_employees']['und']['#options'] = array(
  0 =&gt; t('N/A'),
  1 =&gt; t('No'), 
  2 =&gt; t('Yes')
);

# This would set 'N/A' as default :  
$form['profile_company']['field_employees']['und']['#default_value'] = 0;