There is a price war between the major supermarkets. I have seen...

There is a price war between the major supermarkets. I have seen Free range eggs drop from min of $6dozen to $4 as you identified. It seems eggs are the new battleground as they are a staple food like milk and bread.
I am a small-scale egg producer with 100-odd chooks so i am in direct competition with FRM. The definition of Free range is contentitious and 1000 hens per hectare is intensive free range which Coles and Woolies do. They are not free-roaming but fit the code and are relatively cheap to produce-still $4 retail per dozen is cheap and if FRM want to match this i think their margins are thin. I know the economics of eggs on the micro level.
The market for free range is growing (i sell to butchers not supermarkets) and i suspect CAGE EGGS WILL be phased out (not great news for FRM i feel) It depends on the state but ACT for instance has tough laws about FREE RANGE egg labelling.
Consumer group Choice URGES shoppers to boycott Coles, Woolies and Aldi eggs as they are quasi-Free Range.
How this affects the SP i can't say. FRM has a division which produces cardboard cartons for resell. I asked the bloke who manages this area why did the SP go up so much and he said there had been no internal changes ie no idea. Now its retreating so he may be right.