Our 1 year old maltese puppy is pooping in her crate. She had not done it for almost 8 months and then after a stay in a doggie kennel while we were on vacation she began pooping in her crate during the night.

Crate training depends heavily on the dog's desire to not 'go' in the area where it eats and/or sleeps. Then, there are some dogs that have absolutely no problem sleeping in a dirty crate... yours apparently is not one of them, thankfully.

Boarding kennels sometimes (usually?) are a little slow on keeping the kennel area spotless. After so many days of messy housekeeping at the kennel, she has apparently resigned herself to it, and is continuing the practice at home.

Suggestion? Try to show her differently. Show (remind?) her how nice it is to have a clean 'room' to eat and sleep in. But, you have to be able to tend to her quite often so that she doesn't feel the need to 'go' in her crate/kennel (whatever you call it).

While you are at home, keep her crated and take her out for potty breaks every hour or so. Play with her and let her out of the crate if she protests too much... but just for a little while... you don't want her to think she is being punished. Return her to the crate after a play period, and continue as before. Feed her in her crate, after feeding, up the potty breaks to twice an hour, or until she has a BM. I wouldn't suggest any feedings when you can't tend to her as often, like at night. Do this for several days, and then try her as before she went to the boarding kennel, to see if she has regained the idea that she doesn't have to go in her room... that you will be there to let her out as you had been before. I hope you can see what I am trying to get done, and if so, you can modify it as you see fit as long as she doesn't slip back into her 'new' habits.

I know this seems like a real hassle, but when does anyone take a vacation and return home to find things haven't been just put on hold until you return? As I suggested, I believe this is just a retraining problem. Look for the easy reasons this happened, not anything exotic, unless you can't find anything else. In her case, I think it's pretty obvious, and best of luck.

What time are you feeding this pup and how often. Dogs need a schedule when you are training them.

Thanks for the suggestion. We've been leaving the door open to her crate and keeping her in a small area with a pee pad. She hasn't messed in her crate or on the pee pad since we've left the crate door open giving her the option of using the pee pad. We're going to eventually start closing the crate door and getting up a few times during the night to let her outside to go potty.

That sounds like a good plan. I have crated our dogs, in the evening, and when we are gone for a while, for years, partly because as pups they like to get into things and partly because my wife doesn't completely trust them to 'behave' if we aren't around. Almost like children, we will never know if they will do the right thing until we give them a chance to make the choice on their own.
In your case, I believe she now realizes that a clean 'bedroom' is nice after all, and that she will have ample chances to keep it that way. Another few days may not even be necessary, but certainly won't hurt. Thank you for taking the time to update things with us.