my Heavy forwarder is forwarding events to Splunk indexers. Does link breaking , aggregation etc takes place on indexers again?
If not is there any way to make events to undergo parsing on indexers even though they already got parsed on Heavy Forwarders?
Why would you want to do that, what is your use case?
Splunk doesn't reparse the data at indexer once it's already parsed (cooked) at Heavy forwarder level. You can follow configuration from following post to enable reparsing at indexer.
https://answers.splunk.com/answers/224312/hf1-hf2-indexer-how-to-route-a-set-of-data-that-ha.html
Please note that you can't enable this setting for selected data/sourcetype, so if enabled, it will reparse all data that comes in.