Yea that is something to see especially when you have a 'big bin' or a bin with thousands of roaches - when you put fresh food or a different sweet food in the bin. You see ALL OF THEM come out at once. You see nothing but roaches, you wonder how all of them are even in there. Good and fun sight. My daughter like watching all of them come out 'to eat'. Thousands!
The other fun thing to watch is putting somekind of liquid or soft food in a saucer, or what I use, flat lids filled with baby food. The saucer is surrounded by the roach like a cattle fench and they sip the food. they all circle around the lid and fight for possition looks crazy how many can fit around that saucer to eat.
Then of course they start getting greedy and climbing over each other and fall in. The saucer is not deep so they do not drown. but they will be covered in baby food and will be 'cleaned' by the other roaches. Fun sight. The saucer = fast food drink lid - large.