[Maximo]

Welcome to Yorkie Talk. I'm glad Lucy and Nikko survived their rough start in life. That must have been very hard on all of you.

I agree with Kathy that a belly band would probably help you with Nikko. Use an incontinence pad inside the belly band.

To keep them on the pad when they poop...make sure their little rear ends are trimmed and groomed, and I would check each day that the anus is clean. Extra hair, or tiny bits of leftover fecal matter can disrupt the next poop, and cause your pup concern while pooping. If you are home and able to supervise, train your pups to follow the "stay" command on the pad. My Teddy sometimes needs help and he responds to the stay command. (I say it sweetly and follow with "I'll help you." Teddy know help is good). As KJC recommended, follow up with praise and a reward.

Definitely use positive reinforcement and not punishment, which will only makes matters worse.

Make sure they get regular exercise and drink enough water, both of which will help with pooping. Best wishes!