Unable to use stats on field

I have a field that i'm trying to use for stats. However, kibana is not displaying any data.

In logstash im using ruby code to add the value of two fields into a third one. I'm trying to graph the value of the third one. However, no values show up in the stats pannel.

I've tried using a mutate filter to format the resulting field as float or integer. However, that didn't help.

if [bytes_sent] and [bytes_rcvd] {
      ruby { code => "event['bytes'] = event['bytes_sent'] + event['bytes_rcvd']" }
} else if [bytes_sent] {
mutate {
  rename => [ "bytes_sent", "bytes" ]
}
} elseif [bytes_rcvd] {
mutate {
  rename => [ "bytes_rcvd", "bytes" ]
}
} else { }

logstash output:

      "message" => "2015-03-18T23:59:41.802932-07:00 x.x.x.x id=my_host  sn=my_sn_number  time=\"2015-03-19 00:02:27\"  fw=x.x.x.x  pri=6 c=1024 m=537  msg=\"       Connection Closed\" n=14957  src=x.x.x.x:123:X1  dst=x.x.x.x:123:X1  proto=udp/ntp sent=380 rcvd=380  ",
     "@version" => "1",
   "@timestamp" => "2015-10-14T21:00:52.213Z",
         "path" => "/tmp/sonicwall.log",
         "type" => "fw-sonicwall",
         "tags" => [
    [0] "sonicwall",
    [1] "firewall_log"
],
           "id" => "booth_firewall",
         "time" => "2015-03-19 00:02:27",
          "msg" => "Connection Closed",
        "proto" => "udp/ntp",
    "msg_count" => "14957",
       "msg_id" => "537",
 "msg_category" => "1024",
 "msg_priority" => "6",
"serial_number" => "C0EAE490A1A6",
       "src_ip" => "x.x.x.x",
     "src_port" => "123",
"src_interface" => "X1",
       "dst_ip" => "x.x.x.x",
     "dst_port" => "123",
"dst_interface" => "X1",
       "action" => "Closed",
   "bytes_sent" => 380,
   "bytes_rcvd" => 380,
        "bytes" => 760,
  "application" => "NTP",
"logstash_host" => "logstash-dev",
         "host" => "x.x.x.x"

What is the field mapped as in Elasticsearch?

below is the output from elastic. Ican graph the bytes_rcvd and bytes_sent fields just fine. However, I can't graph the bytes field.

      "bytes" : {
        "type" : "long"
      },
      "bytes_rcvd" : {
        "type" : "long"
      },
      "bytes_sent" : {
        "type" : "long"
      },

Does it show the field in the discover field? And if so does it show the data for it?

The field shows up in discover and the field is populated with data. ie 10.0 (float) or 10 ( integer).

If i make a chart graph or a histogram, terms, etc. the field works as expected. However, it does not work when I try to use it with stats.

for reference I'm pulling log data out of a dell sonicwall NSA firewall and trying to combine the value into a single field so I can compare against dell, juniper, etc firewalls.