I have three dogs, a Westie, Silky Terrier, and a Sheltie. My Sheltie NEVER! Goes to the bathroom inside. In the last week, my sheltie has had runny and clumpy poop twice inside. Now my silky started having the same problem. I have not changed anything in their diet and I am not sure what is going on. Any Suggestions?

More than likely, the dogs have picked up either round worms or whip worms.

Take a sample of their stool to the vet and have it tested for worms.

Normally, if one has them, they all have them.

I agree with donf, could be some sort or parasite or worms.

Don't get angry at them for going inside just yet, it may not be their fault.

Book an appointment with your vet and get a specimen jar (they are available at chemists/pharmacies) and take a sample of your dogs last bowel movement into the vets with you so they can examine it.
Gross, I know, but this way they can easily determine what type of worms your dog has (if any)