My two 24ish week old neutered and wormed cats always do squashy, almost mousse like poos. I've had many cats in the pat and theirs was like beads. What could be causing their squashiness? They are fed quality kitten food, have been deflead and wormed and are otherwise healthy. Getting them to the vet would be very difficult so if anyone can suggest a supplement I can give them, I would be very pleased.
If you went to the vets the first thing they would do is change the diet and see if it improves. So you can try that and if there is no improvement go to the vets.
My older cat often suffers with diarrhoea and I put her on this food and it fixes it within a couple of days. It can be used for a week or so to see if you see an improvement. If you do you can either try your old food again or use it indefinitely. If however it doesn't clear up the problem then you will need to get them to the vet.