The exchange of gases (O2 & CO2) between the alveoli & the blood occurs by simple diffusion: O2 diffusing from the alveoli into the blood & CO2 from the blood into the alveoli. Diffusion requires a concentration gradient. in the alveoli must be kept at a lower lever than in the blood. We do this, of course, by breathing - continuously bringing fresh air (with lots of O2& little CO2) into the lungs & the alveoli. Breathing is an active process - requiring the contraction of skeletal muscles.
Quick Answer. During a rooster injection on a knee, the doctor cleans an injection site near the kneecap, inserts a needle and withdraws any extra fluid from the knee area, and then through the same needle injects a solution containing hyaluronic acid, a substance obtained from rooster combs, into the knee joint, according to WebMD.
4 to 1 ratio is a bit extreme. The rule of thumb is 10 hens to 1 rooster. Less has worked but if they're all the same age and just maturing, your hens are in for a rough time. Roosters grow bigger and mature faster than pullets so when they grow up together the rooster has a tendency to become an aggressive bully.