Longtime listener, first-time caller...

My husband and I live in Chicago, and are expecting our first child, a girl, in August.  We're currently in a search for a day care provider, as she will need care three days a week after I go back to work in October.  What I want to know--is there an etiquette to cold-calling providers?  I have made a couple of inquiries during the day and been rather coldly treated.  Should I call in the evening?  We're trying not to make enemies here...