Why did my puppy start pooping in his crate after several days with no problems?

Might be good to start at the vet to make sure there is nothing wrong with him. Is his crate too large? Puppies need to have a very small area to sleep in, so that there is no room for them to make a mess and still lie down.

Sounds like he just had to go potty. Puppies cannot hold themselves all night like an adult dog can. I'd also advise to take your dog to the vet to make sure there are no health issues that could be causing this. However, puppies need to be taken out very frequently and if they are going potty in the crate it's likely because they have to go. Take them outside more frequently and praise them when they go. Good luck. Puppies are tough and you will have accidents. It happens. Eventually you will get there and they will be old enough to sleep through the night without needing to go potty!

We had problems with our dog also. He used to bark and chew shoes, table etc when we were not at home. We had no time to take our Bud to dog training classes. We asked one friend who works in foster care. He recommended one online dog behavior trainer http://bit.ly/2s3XuQF. It helped us a lot.

All puppies are like this. They start off doing very good than all of a sudden they forget than they remember again. Puppies have a very small bladder and they poop a lot so please be patient. All that training and patients will kick in.