Bad manners

As a child I was always taught that it was bad manners to make a noise while eating.
Since raising silkworms I have read many times that during a visit to a silk farm you could actually hear the worms eating. I have never heard this sound, until recently!!
For the last four weeks I have been feeding 140 silkworms which hatched unexpectedly because I didn't get the eggs into the fridge quickly enough after they were laid and shown to be fertile.
When they are first laid the pin head size eggs are white and almost invisible on kitchen paper. Within a couple of days the eggs start to darken - if they are fertile - then they are stored in the fridge, as they are supposed to need a cold period before they will hatch. Mine hatched in double quick time, probably due to the extra hot spell we had a month ago.
I have never reared so many caterpillars at one time, my poor old mulberry trees have lost a lot of leaves, but I started collecting them from the bottom of the branches which needed pruning anyway so the lawn mower could get under.
Last week, each time the caterpillars were fed, I heard the noise written about. I guess 140 mouths chomping on the freshest, crispest mulberry leaves is the difference. Our sons girlfriend likened it to the sound of rice crispies when the milk is poured on.