LOL when cats do this it means they are saving the food for later and don't want anyone else to find it. Your cat sounds very smart. Maybe he was trying to hide it from you so he could get some chicken.

About the main part of your post, I have had some trouble discarding defense mechanisms from the past, and some success. There is an automatic reaction to use them. I have to be vigilant and try hard not to, when the occasion arises. I want to not have to automatically put them down the old patterns as they arise. I want "the new way" of reacting to become automatic. Don't know if it is possible. I would suggest just starting very small, trying it just one time in therapy and seeing how it goes. You don't have to discard a defense all at once, just slowing try new ways of being. Therapy can be a safe place for that.