IF egg producers sold their eggs at essentially fixed priced contracts those eggs should not cost much more to customers, unless end market sellers wish to make additional money off of the supply/demand situation.
If the egg producers are free to sell their eggs based on supply and demand, or if their contracts were flexible enough to cover their costs with a small profit guaranteed, I can see the consumer egg prices going up.
For some restaurants to charge an extra 50 cents an egg nationwide, that means that is an extra $6 a dozen. Ordinary chicken eggs can still be bought for less than $6 a dozen in most communities. So this 50 cents an egg charge assumes a doubling or more of their egg costs.
How would you like to double your gross margin? Of course, this charge can be used to discourage egg purchases if egg supply is low, but their temporary higher egg costs are covered. Egg prices can be more costly in some parts of the country because of where the chickens had to be killed because of the disease. Higher egg transportation costs can add to the prices. These surcharges may be too high to simply cover the current extraordinary temporary higher costs for the eggs nationwide. These restaurants may argue the prices are only going to go up and they do not wish to raise prices too frequently for their customers. Spin?
Farmers and others often lock in prices and thereby reduce uncertainty with their contracts, sometimes they are called futures.
However prices cannot simply escalate forever, as there is a price point where demand falls off, then prices change to correct the supply and demand imbalance.
Gas stations tend to do price changing to protect profits. They do not usually make all that much per gallon sold however. With enough volume and other sales they can do okay.
When they get a price increase, it tends to be quickly reflected at the pump price, even though the gas in the storage tanks were bought at the lower price. When their costs goes down, the pump price tends to remain higher longer. In other words, higher costs are passed more quickly than lower gas prices are implemented to the end customers.
Of course free market pricing extends to many other situations besides eggs and fuel. Think of how much more hotels charge when a famous singer has a concert or a big sports event may be in their cities. They charge more because they can. The consumer decides if they will pay the price or not. No one is forcing them to buy.
However, when the fires hit Southern California and so many people needed temporary or long term housing, some may argue that even though the demand zoomed, prices should be moderated (and price was by disaster laws) because of humanitarian reasons.