Feed Statistics is a plugin which tracks statistics for RSS or Atom feeds including the number of subscribers which feed readers they are using, which posts they are viewing and which links they are clicking on. One can display subscriber count in two ways and each one is described as below:
1) .One can add the following code to theme
If theme is widget-compatible then one can use the Feed Statistics widget which will display the same text but it will easy to manage through widget.
2) This plugin is adds a “Feed” section into WordPress administration panel. This section has four subsections: Feed (Options), Feed Readers, Post Views, and Clickthroughs.
It will take a few days for the subscriber count to become accurate, so you may want to wait a day or two between installing/activating the plugin and publicly displaying subscriber count.