Chick acts different than others! Help!

[Memeschix9]

I'm a first time Guinea-er. I have 6 guinea's aprox. 5 weeks old. All appeared normal the first week. Then I zoomed in on one. It walks normal but drops both wings nearly to the ground. Body shape doesn't resemble the others due to drooping wings. Walks/Runs but beginning to struggle to keep up! Chirps at a higher pitch and constantly stretches neck out and opens mouth as if more air is needed. Today, walks/runs and entire body is fluffed out. Eats and drinks normal. Assume it's toileting as I'm not seeing the actual action. It's becoming a loaner due to not keeping up. Any advice or diagnosis is welcomed.

 

[gguineasfamily]

Does it walk funny? With a limp? It should be fine but I would suggest getting a chicken or younger keets to keep it company. The reason why wings down , open mouth and fluffed out is because it's hot. This keet isn't as fit as the others. Does it sneeze? I don't think it's sick but a slow companion will be good as it will help it not be lonely.