This is not in Poitou-Charentes but just to the north in Anjou. I know there are plenty of Zoos and wild life venues in Poitou-Charentes and many of them are very good. I have listed the ones I have been to in the Zoo page at the top of this blog.
However I think the Zoo at Doue is the best I have ever been to. The reason is partly because it is on the site of an old quarry and the excavated areas have been very cleverly used to provide the enclosures for the animals. So not only is there a minimal amount of fencing, bars and glass, but also the settings look very realistic. Especially for the African animals you can almost immagine you are out on the plains. I do not know what effect this has on the animals, afterall most zoo animals are today bred in captivity, so would not know what the Serengetti looks like, but I think they might feel more at ease in an African setting than in a green grassy Northern European setting.
We went out of season and it was very relaxing to walk round and enjoy the animals and not have too many Homo sapiens getting in our way. It might get fairly busy mid summer. I would prefer a cool day to visit rather than full sun.