If the next hen deposits a wet dropping on that egg, the coating can dissolve in that spot, the same as if you wash the egg. So it is possible that a heavily soiled egg can pick up bacterial contamination. The egg is at its freshest the instant it is laid. After that, no matter what you do, the egg begins to lose moisture through the shell. The membranes begin to shrink as it loses moisture and the size of the air cell increases.
Heat IS detrimental to egg quality.
In fact, you should probably throw them out. Store hatching eggs in the 50-60 degree range. Refrigerate food grade eggs as soon as you collect them. One thing is for sure, the quart of gasoline will always be a quart of gasoline. But while the fire ant nest may only be one mound today, a month from now it will be 50 and a month from then it will be 50 times 50.