A feral cat knocked on my door and I let him in but when I am outside with him he will eat grass. I beleive it helps his digestion system but since he doesn't talk to me that's what I will assume since there are enough rodents for him to hunt so why eat grass so I don't find it strange that a house cat to want to nibble but there are many cat haters in the world so don't allow your ambition to be denounced.