If you need to redeliver several messages in bulk, click on the Bulk Redeliver button to release the messages that are in the current view:
To release messages for a specified window of time or specify other criteria, click on the advanced link:
After clicking on the Bulk Redeliver button, you'll be prompted to confirm the number of messages that will be released.
To view the status of a redelivery of a bulk release, use the bulk redeliver status tool: