Supermarkets are unilaterally driving the retail price up, whilst at the same time driving down the cost they are paying the farmers. Its not a negotiation, nor are they passing on rising costs to the consumer.
Pure profiteering, and the supermarkets would love you to believe is the cost of feed stock or the energy prices that are driving up the retail prices.
I dont imagine for one minute there is an actual egg shortage, I assume its a shortage of egg farmers willing to sell produce at a loss just to bolster supermarket profits and dividends.