You have done an incredible job as these guys are quite hard to raise. Maybe a stool sample to a vet to see if they have parasites would be a good idea. Ihave attached a link for a woman that has done incredible work with a lot of wild bunnies- though squirrels are her speciality. Email her and she will respond. You may find an answer on her website below.
http://www.hal-pc.org/~jbsum/squirrel.html
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If my answer was helpful please click the green accept button My answer should not take the place of a Vet's diagnosis when needed. Positive feedback is most welcome and a bonus-though not required-is greatly appreciated no matter how small.

