Feeding canned, soft stools at night

I've been feeding Wellness Core canned Turkey and Duck for almost a month. I've noticed in the past few days that the cat's last bowel movement is a little soft. She was leaving a trail a coupled of nights ago and I had to clean off her bottom. I have added a little bit of kibble to her food-the same kind Wellness Core Turkey and Duck. She had been on antibiotics for a long time but she went off those about a week and a half ago. I'm wondering if she needs probiotics now. Any thoughts?

I am a firm believer in giving Probiotics.  All three of my cats get them, all the time.

What I don't quite understand is why only the last poop of the day would be softer when eating the same food all the time.  Time of day should make absolutely no difference.  Antibiotics can definitely mess up the digestive tract though, so I would absolutely get her on some good probiotics and see what happens.  You don't need to use pet probiotics, IMHO.  I give mine the same ones WE take

Here's a good article on the subject:  http://www.thecatsite.com/t/266113/does-my-cat-need-probiotics