Yaoi one shot where the world was infected with parasites that made people's appearance that of animals/creatures except they change back once per year on their birthday? (one of the main characters looks typically human, the other one has Eagle like characteristics)
It shiuld be this chapter
http://www.mangago.me/read-manga/kemono_jingai_bl/mf/v01/c004/1/
I don't really much about the yaoi manga except for the side story chapter. The side story has this high school student who's blond and has the stereotypical pompadour hairstyle. He's an uke and unlike his image, was really nice. And his eyes are shut constantly. Anyways because of his hair, he was always mistaken for being a delinquent and was forced into fights. Since he's always forced into fights, he's pretty good at fighting. Oh! And he was best friends with the main couple.
I know the main story is about 2 dads with a kid each who get together. the side story is about the sons. the blonde kid is fat and goes away with his dad to lose weight so he can be with the other kid. he comes back cute & skinny, they get together but then he goes back to being fat.
Ff
I'm so sorry I spent the past probably 30 something minutes searching for the manga I tried really hard... Ff...