my dog keeps pooping in my room. Help!

[o0Janice0o]

one of my dog (tiger) recently who is potty trained, had started pooping in my bedroom in the middle of the night.  let me give you the facts: he is 5 years old with a 4 year old brother.  we recently (4 months ago moved into a new house with my sisters)one of my sisters has a newborn baby (2 months old). the sleep routine is that they both sleep with my sister because my sister wants the other dog to sleep with her and tiger can't sleep without his brother.  at 3:20am my sister brings the dogs outside and then brings them to my room because she goes to work at 3:30. No more than 10 to 20 minutes later my dog poops in my room(i wake up to hearing him move around and find the poop).  this had been happening everyday for the past week. he knows what he is doing is wrong because he hides everytime he sees me see it. i tell him no bad boy and put him outside.  my sister even had been extending how long she puts him outside to ensure he has enough time to do his business but he still does it.  i dont know what to do anymore.  he also used to before the move sleep on my bed but i trained him to sleep on his own dog bed.  idk if that is effecting him.  

[ginger899]

Okay....you say at 3.20 am your sister takes the dogs outside....yet she has to be at work at 3.30! I don't obviously know how long it takes her to get to work. It might only be two minutes. But that is an average of five to eight minutes outside. Or less??
Has your dog had enough time to sniff about trot around, go round in circles (like they do) and do his business? They can't always poop to order any more than we can. If someone said to you "You have five minutes to poop right now." Would that work for you?

What sort of exercise and proper structured walks does your dog get during the day, and does he get a walk a few hours after his evening meal....say 20-30 minutes?

If you live in an area where night walking is unsafe, then the best plan is to walk him in the day and feed him his main meal early afternoon, to give his digestion time to work. But make sure he gets proper walks. Like us -ofetn a little exercise can make them "go".

I am looking firstly at any obvious physical reasons rather than behavioural.

If the other dog doesn't do the same, then again -it's like us! All dogs are individuals and have different ways and different bodily needs.

[o0Janice0o]

i guess i worded that wrong she brings the dogs in at 3:20 but brings them outside as soon as she wakes up and leaves them outside until she finishes getting ready so around 45 minutes outside.  we walk them every morning and afternoon and have a spacious backyard. walking at night is a no go because of safety. but recently i had my sister wake me up right when she brings them downstairs.  And I would lay him down and pet him until he looked comfortable and go back to bed.  and he hasn't pooped since... weird its like he did it all for attention.