Are you caching the results on your server? You should cache the results for a better response time. That way you can return more information to the browser without checking availability for the same queries over and over.

For example, save the availability of picklenickel.com for 24 hours (or maybe more I don't know). Then you can do some recursive calls using cached data. Making all those concurrent HTTP requests seems impractical and has to be affecting your server's responsiveness.