Toy Poodle digestive problem

Question
My toy poodle is 13 years old, weighs 2.6kg, has cataracts.  She eats rice and chicken chopped up with warm water, as she won't drink water on its own.  Last Christmas she couldn't poo and had a swollen stomach.  She obviously had a stomach ache, as was walking around and doing downward dog.  Our visit to the vets, said all her organs were healthy and had no explanation why she was so distressed.  They gave her pain medication and we took her home, massaged her stomach and finally she broke some wind several times and then did runny poos.  This same problem has come up again with runny black poos and she is straining all the time.  We have tried the massage again and this has seemed to help, she went off her food for a day, but now is back on it.  This time she has come through quickly without a vet visit.  I am wondering why this happens in the first place?  Should we feed her lamb and rice instead of chicken tendaloin and rice?  She still strains to go to poo, could it be a twist in her intestines?  She is happy and sleeps most of the day and hates going for walks, as I believe of her blindness, but follows me around the house, up and down stairs all day long.  What else can be done to help her and make her comfortable if this happens again?  
Thanks so much, Annalisa

Answer
Perhaps rather than me, you need to be talking to a different vet.  In some ways, the continuing problems suggest some sort of a blockage, the twisted intestine or a foreign  object.  Has your vet done X-Rays?  It is surprising how well soft tissue and other material shows up in a modern X-Ray.  

I question long term feeding the chicken and rice.  It is fine temporarily for firming up a dog, but isn't the complete and balanced diet dogs need.  I think she would be better off on one of the common commercial dog foods.  Better nutrition might help some of her problems.