I’ve stolen two cats in the last four years.
One from a neighbour who threw it out and didn’t bother feeding it or getting veterinary treatment for it’s obvious skin sores....bleeding in places. I. Fact the cat was in such a state I thought it was a stray...it was thin too.
After asking around (including neighbour) and everyone denying ownership I took it to the PDSA for health check. They weighed her and she was just 2.5kg....seriously underfed. Her sores were a severe flea allergy and she needed antibiotics and steroids to treat them as they were so severe.
Eventually the neighbour told me the cat was hers but asked if I wanted it as she didn’t have time. That was four years ago....said cat is now 4.2kg, haas clear skin thanks to monthly flea treatment and is snuggled up on a fleece on the back of the sofa.
Cat number two was one of a pair who ran into peoples homes and ate voraciously. At first it was funny,...the biggest cat was known as “Six dinner Sid” locally and we just assumed he was a thief. Cat number two joined him a few months later....from the same house and also voraciously hungry. They never went indoors and were left out during firework night two years ago and also on cold and freezing nights.
The RSPCA eventually got involved but while they were investigating the neighbours did a bunk....literally left owing god knows how much rent. They left both cats behind. My niece has one and a local cat rescue rehomed the other...
Two cats stolen....both neglected to various degrees with owners who couldn’t give a stuff for them.
That said...
I wouldn’t ever just feed a cat. I’m not one to take other peoples pets and the two cases above are fairly unique over my 50year lifetime.