There is some research on the placing of feed trained LMB into existing populations of natural non-feed trained LMB. I have not looked at it in a while but the feed trained LMB did not do so well. There is other research that is not as conclusively negative. That is why if one is buying advanced LMB for stocking (6 inch or larger) that are feed trained it is better to get them that were placed into a growout pond at the hatchery including live forage. That is supplementally feed but not substantially reliant on feed.