I have 2 shetland sheepdogs that are almost 4months old...By surprise the difference in both and concern is there size. Female is approxiamately 10 1/2 inches and the male is 15 inches at this age. I was planning on breeding but Im thinking it may not be such a good idea. The female is still so much smaller than the male and she may not beable to carry and cause some problems. If anyone has an idea about size in breeding shelties..I would appreciate any input on this topic. Please or any website that may have any information pertaining to this..