Mead in secondary, looks to be going well. However, the lighting isn't totally dark. Also, there is a single dog hair in the carboy, but not touching the mead. There seems to be very little oxygen, if any in the carboy. Should I take the hair out? Will the lighting or hair spoil the mead?
Since it's on secondary, contamination risk is low, but for contaminants that have contact with the drink from now on. If the hair is there since the beginning of the fermentation, any possible contamination has already happened. Either way, it's better to remove the hair than to leave it there.
Minor lighting shouldn't be a problem, sanitation is much more critical to the final result of a mead. My main concern is what the dog hair indicates about your sanitation process.