When a baby squirrel is skinny dose that mean it is sick?

If you have a baby squirrel it needs to go to wildlife rehabber in your area. This is free for all wildlife. It may have disease it may be under nourished from poor diet. How old is it? If young needs to be fed with a syinge or bottle. Needs Esbilac 6-8 feedings a day. If getting bigger can give cheerios and other natural foods it eats in wild. They love grapes. If this is a wild squirrel outside than put food out for it as it may not have hunting skills it needs yet to find food properly. If trying to raise it yourself do yourself and it a favor and get it to rehabber as it will probably die. Not saying your intentions are not good but needs proper diet and care and then to be released. Good luck.