Can I give leads a pre qualification questionnaire?

[Jehan Jaleel]

Hi, I am a total newbie landlord. I am trying to rent out my house. So far I have posted my home on Zillow (and partner sites) as well as Craiglist. I think it is competitively priced with other houses which have around the same number of bedrooms, baths and square feet (I found others slightly lower than mine and some higher). 

So far in about a week I have gotten about 5 leads via email. But to save their time and mine I have asked them to fill out a small questionnaire before I schedule a showing. This questionnaire asks how long they have stayed at their current place, why they are looking to move, their income, credit score, number of people, etc. But almost every lead went dead after this questionnaire. So what is it right for me to send this or should I be pre screening some other way (if it all)?

Also a somewhat unrelated question, is there a specific credit score I should expect potential tenants to have?

Thanks.