When using the apex:inputfield tag on an Owner field, the styling can get broken if a queue can own the record:

This is because an extra div is brought in to contain the individual elements and this div has the "form-control" class applied.
There is a workaround - Add the following code to your javascript:
$("[id$=mlktp]").hide();
("[id$=FIELDID_top]").removeClass("form-control");
$("[id$=FIELDID],[id$=FIELDID_lkwgt]").addClass("form-control");
Where "FIELDID" is the id you've assigned to the ownerId field.