jquery validation doesn't work chzn-select

Question

I'm using jquery validation. Other field validations are working well except chzn-select.

<script>
    jQuery(document).ready(function() {   
        FormValidation.init();
    });

    $(function() {          
        $(".chzn-select").chosen();
    });
</script>

html code

<select name="op[]" class="chzn-select" style="width:400px;" required>
    <option value="">Select</option>
    <option value="1">chose 1</option>
    <option value="2">chose 2</option>
</select>