I just wanted to share my experience with trying to raise a baby red squirrel to share all the problems I encountered and solutions I tried, for the benefit of others.
I had a baby squirrel following me in the woods one day and so I picked it up, not knowing if it would bite me or what it would do, but I found out they are extremely lovable little animals.
I wanted to feed it whatever it wanted, and bought it lots of expensive nuts, almonds, pecans, peanuts. I had no idea that pecans are like crack to little squirrels, I witnessed her downward spiral as she refused more and more types of foods til she would only eat pecans. I put chocolate syrup in her milk formula and would always give her that before I gave her pecans, though, so she was very healthy up til about 10 weeks. I figured her bones were developed well enough, and she just stopped drinking the milk, I thought it was ok after they were past the weaning stage, but in about 5 days, after she completely stopped drinking the milk, she just started sleeping all day. Luckily I looked it up on the internet and found out that was a symptom of metabolic bone disease. Also, a little bit of hair came out of her tail, her tail began to thin, which also is a symptom of metabolic bone disease.
I read that calcium citrate is absorbed the fastest, but is more expensive so is not usually used in commercial supplements, but I crushed up a citrical pill, and mixed it with peanut butter and she gobbled a whole bunch of it and I knew she had gotten a massive dose of highly absorbable calcium. She went back to sleep for 4 hours and when she woke up she was like a new squirrel, running around for hours, leaping onto me, leaping onto everything, exploring everything like it was all new again.
Luckily I recognized these symptoms within a few days of the disease beginning, and little harm was done, and was easily reversed.
I just wanted to add my experience in case it might help someone, I really understand why people love their squirrels, I understand how it would hurt to see them suffer so much from such a nasty disease.
I would also add, I downloaded a neat little program for my webcam, with motion detection software that I used to track her behavior, which really helped monitor her, while I was gone. It was free and it was just a cheap little webcam but it actually worked fairly well, although the file sizes are massive and it takes a little tweaking and experimenting to get it just right.