He is experienced. The feed is in large hoppers that they generally have no trouble getting food from and he was checking them every second day. So I am confident that this wasn't the issue.
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The aviaries are 2 thirds roof and sides and 1 third open wire. So there are areas open to the elements but Ive had the aviaries for about 5 years now in the same spot and never had an issue of this nature. Some family suggested it may have been the extreme weather that was on at the time but again that has happened before and I have no issues.
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He didn't take them to a vet for testing.