overnight pooping

Question
We have a one year old beagle mix and a 2 year old mutt that we're not sure what he is.  Both dogs were adopted from a shelter.  The younger beagle mix has been potty trained for a while now but has recently started to poop on the floor while we are asleep.  Last night, I took him out for ten minutes to use the bathroom and he wouldn't.  Instead, he came inside and pooped on the floor.  We've tried to feed him just in the morning but I don't think that is the problem.  Any ideas on why his behavior suddenly changed and how we can retrain him?

Answer
Why his behavior changed:    When a dog's behavior changes, we need to look at what has changed around him as well as possibly inside him.  Is he possibly sick?  Is he stressed?  If your dog is acting sluggish and different than normal, then it is possible that he is sick.  If this is the case, ask a vet (or a vet expert from this site) about it.  It is also possible that he feels stressed.  New and/or different situations trigger stress in certain dogs, which can cause the dog to revert back to inappropriate behaviors.  Depending on the background and genetics of the dog, some dogs are more sensitive to change than other dogs.  It is also possible that if you or one of your family members feels stressed, your dog is reacting to that stress, by feeling bothered as well.  Regardless of why your dog's behavior changed, one of your main focuses, in terms of your response, needs to be patience.  

How to change the behavior:  Since the behavior occurs when you are asleep, it may be more difficult to change the behavior.  Here are some suggestions:
1.  Stay up late one night, and figure out about what time your dog poops in the house.  Dogs that do a behavior routinely generally have a routine time that they do that behavior.  If you figure out a general time-period that your dog does his business, you can stop him in the act.  
2.  If you figure out the time that your dog goes potty in the middle of the night, then wake up a little bit before that time and potty him.  Reward him profusely if he potties outside.  If he doesn't potty at that time, then wait a little bit and take him out at the time that he generally goes potty.  Overtime, extend the amount of time between when you go to sleep and when he generally potties in the house.  Wake up a little bit later each night, and challenge your dog to hold his bladder a little bit longer.  If he goes back to pottying in the house while you are asleep, you may need to start over again.  If you choose to use this approach, use very small steps.  If you take it too fast, then he may not be able to keep up with you.
3.  Make sure that you STILL rewarding him profusely when he goes potty outside.  Even though he may already be "potty trained," you want him to continue to believe that every time he potties outside, he is the most wonderful dog in the world.
4.   Keep him confined to a certain location during the night.  If your dog is not frightened of the kennel, I suggest that he stays in one while you sleep.  If your dog does not mind lying in his own poop, then a kennel may not be the best solution...
5.  You  may need to take your dog out to potty more during the night.  If you wake up in the middle of the night to go the bathroom, take your dog out to potty as well.
6.  Take your dog on a long walk (example: 30 minutes to 1 hour).  Give your dog PLENTLY of opportunities to potty on the walk.  Movement oftentimes stimulates the bowels.
7.  Offer your dog lots of water throughout the day and especially right before the walk.  You want to prevent constipation, because doing so will give your dog a chance to get rid of all of the excess food that he ate from breakfast that morning.
8.  If none of these suggestions are helpful, and if you have honestly done all of these suggestions to the best of your ability, then I would say ask your vet.  There may be something wrong with your dog's health.

I hope that this information is helpful.  Please respond to this post if you need more assistance!