An overweight doe is one to be watchful of from the beginning of her pregnancy. Overweight does tend to have difficulty during pregnancy and especially delivery. They are more susceptible to pregnancy toxemia. If your does tend to be overweight, as many does used for show are, you may want to put them on a diet before breeding. Checking for ketosis can easily be accomplished using "keto-strips" which are readily available at your local pharmacy. A doe that isolates herself from the rest of the herd, before her kidding due date, is one you should check for ketosis, if the test strip is abnormal a call to the your vet may be wise.