I have a chicken with significantly impaired vision. It is my favourite chicken!!! Takes some extra time and wide bowls, but manageable.
You would most likely be more concerned with other damage and the risk of infection. Try to get as much food/liquid into the animal and add an antibiotic as...
The chickens at the grocery store are most likely inhumanely or, should I say, unchickenly treated, to maximise growth and profit. The point of 'backyard chickens', I thought, was to do better than that...
Tough call, if the skull is open it will most likely get an infection. If you want to save it, you would need antibiotics at the very least. As much as I love animals, it might have a hard time surviving. This sucks... sorry!!!
Perhaps this will fix itself with age, since your roo is about a month younger. Eventually his testosterone will kick in (maybe around 4 months old) and he will likely kick the hens butts. Perhaps it is better that you get along with him, because that tends to be the bigger problem with chicken...
Not sure, but there is also the option that one or more chicken were sick and infected the others during the trip due to proximity, etc. But, more likely, the weakest ones died after the journey, in which case it should taper off now. It the dyeing persists I would think it is disease.
Think...
If you are not willing to spend the minimal money to keep one-week old animals at the correct temperature, maybe this isn't the right endeavour for you?
Not sure I would risk having my chicks die or suffer to save a few bucks on electricity... I have used a heating blanket under the box in the past and that has worked fine.