>>53306437Dragon Week in August 2020 was infamous for making Deino virtually unattainable from 7KM eggs, despite being the selling point of the event.
https://pokemongolive.com/en/post/pokemongofest2020-ultraunlock>The following Pokémon will be hatching from 7 km Eggs: Horsea, Dratini, Trapinch, Swablu, and Bagon. Gible and Deino will also be hatching from 7 km Eggs, but only if you’re lucky!There was a strong backlash which prompted Niantic to disclose odds of egg contents (albeit in a vague manner), and rethink the probabilities of hatching any particular thing.
https://thesilphroad.com/science/quick-discovery/deino-reviewing-dragon-week-hatches 