It is absolutely a myth that feeding in the enclosure causes cage aggression. Our collection is a pretty decent size (at the peak of hatching season it is usually around 200 BPs). We feed everyone in their tubs and have no issues with anybody being aggressive. If you think about it, it makes sense. Everyone's tub gets opened once a day at a minimum (sometimes more if we are checking for locks/eggs), so one out of 7+ tub openings leads to food. Plus, if you feed outside of the enclosure, you then have to move a snake that is in feeding mode, which increases the chances of being bitten. Another thing- if snakes really did make such a strong association with regards to where their food comes from, moving them to feed them probably wouldn't help anyway. They would just learn that being taken out means that food is coming and become aggressive when they were removed from their enclosures.