To understand animal wellbeing. we need to consider subjective phenomena and sentience. This is challenging. since these properties are private and cannot be observed directly. https://www.spidertattooz.com/Messerschmitt-Me262A-1A-Fighter-Aircraft-LT-Walter-Hagenah-III-Jagdeschwader-7-Larz-Airfield-Germany-1945-German-Luft/