Ava is an interesting case. It isn't the crate per se, but the underlying fear of confinement, which also applies to babygates, closed doors and X-pens. The crate is the worst, because claustrophobia comes into play. Now, Ava will willingly go into her crate to eat, drink, earn treats or play crate games. The issue comes when the door closes. At first, it was pure, wild, uncontrollable panic. That was when she had the explosive diarrhea, beat her paws against the door and twisted frantically around and around, hurling her body against the crate. I can't bear to remember that stage. We got a little past that and worked our way up to shutting the door while she ate… or had a bully stick. I would be right there and would open the door the second I sensed anxiety. The next stage will be even tougher, because it layers in the separation anxiety, which we are addressing with other techniques.
I revisit all this, because eeeefarm makes some good points, in that desensitization is a mix of positives and soft negatives. There are unwelcome consequences for unwanted behaviors. For example, at first, Ava would have a few bites of food, then want the crate door to be opened. I immediately opened the door, she came out and then I closed it and made her wait five minutes before she could get back in and eat. She was hungry, so this was negative reinforcement. It didn't hurt her and she always got her full meal, even if it took hours. And it worked. Now, I put her food in the crate and lock the door 5 minutes before I let her in to eat. She can't wait to get IN the crate. There's always something good waiting for her in there. I have never used the crate for punishment, and I never put her in it when I'm upset, so she won't pick up bad vibes.
Mixed in with the densentization therapy is NILIF, which is also a mix of positives and soft negatives. Ava has to sit outside her closed crate for a drink of water. She can have it any time she wants it, as much as she wants, but she has to sit and ask for the crate door to be opened. Viewed from this perspective, even clicker training can be a tradeoff of negative and positive-- Ava would probably rather continue digging in the flowerbed than come running at my command, but the treat compensates for having to give up something fun. Back-chaining sounds intriguing. I have read Karen Pryor, and it sounds vaguely familiar, but I'll have to go back and refresh my memory.
I do want to reiterate that none of this has ever hurt Ava or caused physical pain. The Martingale is as harsh as I've gotten. I think it's interesting and informative to share opinions, which is why I post about this-- to get helpful advice from others and perhaps help someone else cope with a difficult situation. After living with a Fanconi dog for 9 years and now dealing with Miss Ava's smorgasbord of problems, I find myself a fount of information-- yet every day I find that I know nothing at all!
) But even actual pain is relative. Psychological pain can do far more harm than physical pain, which can be a useful thing and teaches you to keep your hands off a hot stove. 
