My 17 week old Bichon Frise gets so freaked out when he is put in the crate and left alone that it makes him poop. He is given ample opportunity to go before I leave and generally he is only left in the crate for 1 hr a few times a week, other than sleeping. He has learned to be in the crate at night though I respond to his barking for the first 1/2 hour or so to take him out to see if he has to go, as experience has shown me he may have to poop so I do keep showing him that the only thing he will get from barking is a trip outside which is not that fun if its cold and wet. I tried to ignore the barking when initially put in crate at bedtime he would poop in the crate. So now by the end of about 45 min of repeated trips out, he has either pooped or decided to capitulate and go to sleep. He usually barks at 3:00a.m. to go pee then back to sleep with no problem and occasionally he barks to get up to poop in the middle of the night. I am feeding Nutro at 4:45 and stop water at 7:00.
Back to the original question: he seems to have the hallmarks of a dog with separation anxiety: We are second owners; he doesn't like to have me out of his sight; he pants almost hyperventilating and sounds perfectly simian ultimately resulting in an off-schedule poop when put in his crate and left alone in the day. Since I don't leave him everyday, I do see that it's not that he has to poop at 3:00 and no body can take him out because when I am there he doesn't poop until after he eats about 4:45. I can't leave food-type comfort toys with him because it would only further stimulate his bowels.
Have you heard anything about the dog pheramone called Comfort Zone to calm what appears to me to be a dog very anxious about being alone in the house?

I don't like the term ''separation anxiety'', too much like psycho babble for me. However, stress, fear, resentment from being left alone is very real. Despite what you read about dogs not fouling their sleeping area, some of them do. You could try lying down next to the crate like you were going to sleep there, and talking to the dog. I have found that highly effective with a new puppy, and somebody else recently posted using it successfully. I have been very successful putting a grid or something to hold the puppy up out of urine, but it doesn't work near as well with stools. A Bichon will be a big mess after laying in them. You could try wood chips. It could be that it will improve before long once he begins to trust you to return.

Giving him good leadership should help too. Dogs see all the people and dogs in the household as a pack with each having their own rank in the pack and a top dog. Life is much easier if the 2 legged pack members outrank the 4 legged ones. You can learn to play the role of top dog by reading some books or going to a good obedience class. A good obedience class or book is about you being top dog, not about rewarding standard commands with a treat. Start at Raising Your Dog with the Monks of New Skete Here are some other gentle ways of making the point:

''Elevation for small puppies: Sit on the floor and gently put your hands around your pup's middle, below his front legs, and lift him up. He is facing you. Hold him for 15 seconds. Repeat until he no longer struggles. If he is past 10-12 weeks, lift his front feet off the ground, but don't pick him up.

Cradling for small puppies: Hold your puppy gently on his back, as you would cradle a small baby. If he struggles, hold him firmly until he quiets for 10-15 seconds. With larger pups, you can do this as your sit on the floor, with your pup between your legs.

Quiet lying down: Place your pup on the floor on his side, with all 4 legs pointing away from you. Use your hands on his neck/shoulder area and middle, to hold him in this position. When he is quiet, praise him. Lengthen the time that you keep him quietly in this position. When he accepts this position well, handle his paws and muzzle, while keeping him quiet.''

The quotes mean this isn't my original work. It is copied from my Puppy Raising Manual. I have long used these or minor variations of them, and they are very effective. You may want to give him a belly rub while he is on his back too. Helps bonding. There is a big difference between him rolling over and demanding a belly rub, and you choosing a time to roll him over and rub his belly. The latter cements your place as pack leader.

As top dog, you have the right to leave the puppy behind. Dogs are much more likely to accept something if they have the leadership they need.

I haven't heard of that product. I am slow to use products like that. This may be a case for trying it.

I Noticed Labman repeatedly uses the answers given below for many different situations. I also know that this comment was made a long time ago but for further information I felt the need to comment.
Separation Anxiety is a common disorders found in dogs, it is when the dog becomes too attached to the owner and become anxious and stressed without their presence. Dogs are not capable of resentment, they learn through experience but do not hold grudges.
The first question I would have asked you was, how long was the puppy conditioned to the crate before being locked in. Puppies need time to get used to new things and a crate can be a frightening experience if they have never been in one before. The door of the crate should be left open all day so the dog becomes comfortable, and feels secure in there and can leave at anytime. Toys can be placed in the crate so the puppy feels more comfortable entering.
Once the puppy has been slowly weaned to the crate it can be locked in only for a couple of minutes for the first time after that increase the time each time it goes in. The puppy should then be comfotable in their crate, the problem left to solve would be the attachment to the owner.
Its important for the puppy to learn that when the owner leaves the house they are going to return, and that when the owner returns its not a big thing, not something to get over excited about. The excitement of the owner returning is what makes the dog anxious in the first place.
So when entering the house after leaving the puppy an owner should not show the dog attention immediately, Enter the house, unpack the shopping, pop the kettle on and then when the situation is calm again show attention to the dog.