This particular error almost always means that the remote HTTP client closed the connection before the server delivered the entire response. This is fairly common on the public web with unreliable network connections, buggy browsers, etc. and usually doesn't indicate an error.
I usually recommend running a service like ChronAm behind a caching proxy like Varnish (http://varnish-cache.org/) or Traffic Server (http://trafficserver.apache.org/) which will soak up a large percentage of dodgy client behaviour and usually also reduces the total server load. In this scenario, the response is delivered entirely to the cache even if the client disconnects and should they reconnect the response should be able to be delivered directly from the cache without the backend processing another request.