dynamic checkbox with icheck style

I'm using icheck for some cool checkboxes but there's a problem.

When I load the page, the initial checkboxes have the correct style, but when I append checkboxes with jquery, the new checkboxes aren't displaying themselves.

here's some code :

this is the checkboxes that are loaded with HTML / TWIG when the page is opened, they are displayed

then :

text_checkbx = '<label class="ckbox">Valider<input type="checkbox" name="validate"></label>'

this is the exact same code than the HTML for the append in JQUERY

text = text + text_checkbx + '</div>';
$('.crawl-body').append(text);
$('.crawl-body').iCheck();

the weird thing I noticed is that with the developper tool, it's as if a icheck checkbox was there but nothing was shown.

thanks if you could share ideas with me

I'm not english so don't shout if there's some mistakes, just edit please