Strange Cat Behavior!

I am a lover of animals, this it the reason why i am setting up this blog because i feel that a passion is a thing that should be shared with everyone around the world. something happened not too long ago that caught my attention and i thought you guys should know about  it.
it is about cat behavior. before now there were four cats living in my church compound which I'm not sure belongs to any specific person. They were all looking so healthy and beautiful before their mother left them. even while their mother was still with them, they had plenty to eat at all times because of the food court that was right where they lived at that time (this was the year 2010). There was a restructuring of the environment and the food court was part of the things that was taken out of the main compound. The four cats had plenty to eat because of this food court, but now that it is gone and the availability of food gradually coming to a halt, three out of the four cats had to  relocate for "greener pasture", but one stayed back. i wanted to know where it was that they relocated to so i had to look for them. To my amazement, i found out that the three cats were able to find the new place where the food court was transferred to. sorry, i didn't tell you earlier that the restructuring that took place did not take out the food court totally away from the church, it only relocated it to the car pack which was behind the church auditorium.
Over a period of time i was expecting and hoping that the fourth cat which happened to be the youngest amongst them would  go out in search for food but i was surprised it didn't it rather chose to stay back. The cat grew slimmer and bony as you can see the rib bone just at a glance because all it got to eat was crumbs from the snacks people ate. Definitely from the look of things, the crumbs were not enough to keep it healthy and strong. and now it looks very thin and bony compared to her siblings that are getting fat from plenty of food they get everyday from the trash cans.

so this strange behavior pops a question in my mind. why would a cat not look for a way to get food even when its almost dying of hunger? i know that cats are naturally lazy but definitely not to this point. so, what is really the cause of this strange behavior? This is just too much a prize to pay for ignorance and laziness.