Your chickens have fowl pox, a virus from mosquitoes. You can put some Neosporin ointment in the eyes of the one with scabs around the eyes, and any scabs away from eyes, you can apply some iodine to help dry them up. Dry fowl pox will run it's course over 3 weeks. Wet pox involves lesions in the throat and airway, and is very serious, so any that look particularly sick, I would look inside their beaks and throats for yellow lesions. Here is some info: https://www.backyardchickens.com/a/avian-pox-how-to-treat-your-chickens-for-avian-pox Below is another picture of similar pox like the top picture:
I've seen the small spots on a couple hens last year. Like you said, they went away on their own after a while. I had no idea it could get as bad as the first pic. I was afraid I would need to put her down.
Are the eggs good while they have this ?
The eggs are fine to eat, but there may be a decrease in production. Just make sure that she is eating and drinking enough because the ones who are more seriously affected can die from not eating well enough. Watch for any secondary skin infections. There's not a lot you can do, but if they stop eating, you can always learn how to crop feed. Here is an excerpt from Merck Manual:
The cutaneous form of fowlpox is characterized by nodular lesions on various parts of the unfeathered skin of chickens and on the head and upper neck of turkeys. Generalized lesions of feathered skin may also be seen. In some cases, lesions are limited chiefly to the feet and legs. The lesion is initially a raised, blanched, nodular area that enlarges, becomes yellowish, and progresses to a thick, dark scab. Multiple lesions usually develop and often coalesce. Lesions in various stages of development may be found on the same bird. Localization around the nostrils may cause nasal discharge. Cutaneous lesions on the eyelids may cause complete closure of one or both eyes. Only a few birds develop cutaneous lesions at one time. Lesions are prominent in some birds and may significantly decrease flock performance.
In the diphtheritic form of fowlpox, lesions develop on the mucous membranes of the mouth, esophagus, pharynx, larynx, and trachea (wetpox or fowl diphtheria). Occasionally, lesions are seen almost exclusively in one or more of these sites. Caseous patches firmly adherent to the mucosa of the larynx and mouth or proliferative masses may develop. Mouth lesions interfere with feeding. Tracheal lesions cause difficulty in respiration. Laryngeal and tracheal lesions in chickens must be differentiated from those of infectious laryngotracheitis (see Infectious Laryngotracheitis), which is caused by a herpesvirus. In cases of systemic infection caused by virulent fowlpox virus strains, lesions may be seen in internal organs. More than one form of the disease, ie, cutaneous, diphtheritic, and/or systemic, may be seen in a single bird.
Often, the course of the disease in a flock is protracted. Extensive infection in a layer flock results in decreased egg production. Cutaneous infections alone ordinarily cause low or moderate mortality, and these flocks generally return to normal production after recovery. Mortality is usually high in diphtheritic or systemic infections.