We can only see a small part of the electromagnetic spectrum
Hearing.
The process of hearing starts by pressure waves that are captured by our ears and taken inside the ear by the ear canal reaching firstly the ear drum. The ear drum then vibrates according to the pressure waves that were captured making the acicular (a set of 3 little bones) enter in motion. This vibrations then move from the acicular to the inner ear. Within the inner ear we can find the cochlea which is where this mechanical waves are converted into electrical signals and then passed to the brain. The auditory cortex of the brain then interprets this signals as sounds and gives them meaning.
Well to begin with this process is called genetic engineering, the scientists altered the DNA of the chickens instead of altering a protein already in the chickens because when you alter the DNA the offsprings of the chicken will will have the same qualities while if you only alter the protein already in that chicken only that chicken will be able to do the job