It's true, I saw a plate of dog biscuits covered in roaches once. They were so many you couldn't even see the biscuits.
On the other hand, it can be a good roach trap. Leave a plate with dog biscuits outside then go there in the middle of the night when the roaches are having an all you can eat buffet and spray the living shit out of them with a can of baygon or similar. Clear out the 20+ dead roaches in the morning.