This sounds like stiffness to me I know im fairly a novice but i did have theif pouters when i was younger and knew a lot of guys who were involved in them too! for youz who dont know about the thief pouters they are kept in individual pens and cant flap there wings most of the time and when in the moult some doomen never put there doos out or bad weather etc and before you know it months have past and the bird does become stiff they looked a picture of health but just wouldnt/couldnt fly and there was no way back for them the never really flew again or went to the building and back! This might be completely wrong but it did happen in the pouters hope you get it sorted George