It is appropriate to mention that you plan to rank a program highly but I wouldn't expect much of a response from them or would, at the very least, be wary of taking any response to heart. Programs are under a lot of restrictions about what they can tell applicants - that doesn't mean that some don't try and get around these.
Rather than asking the PD what your chances are (as I suspect any answer you get might not really give you much information, will be pretty vague), you might ask current residents how programs show their interest (ie, do ALL interviewees get follow-up letters), etc. Make sure whomever you share this information with knows WHY you want to rank their program highly.