First of the series Chiharu and Kazuki only show up in because it's not their story but you gotta read it to kinda understand those two.
1- http://www.mangago.me/read-manga/happy_yarou_wedding/
2- http://www.mangago.me/read-manga/beautiful_beast/ <------ This is officially where you really start their story.
Redpanda42 . Posted the full list above!
How about the second volume
Sorry. No idea. Wish I knew. (￣∇￣")
（/TДT)/
1. http://www.mangago.me/read-manga/beautiful_beast/
2. http://www.mangago.me/read-manga/toriko_ni_natta_kemono/
3. http://www.mangago.me/read-manga/kemono_wa_ai_de_iyasareru/
4. http://www.mangago.me/read-manga/oboreru_kemono_no_koibito/
5. http://www.mangago.me/read-manga/amaeta_kemono_no_shitsukekata/
6. http://www.mangago.me/read-manga/torawareta_amai_kemonotachi/
Can someone tell me...the first volume of chiharu..until the end...because the volume kind of messed up...