I have a doe who I'm starting to milk. She just had kids about three weeks ago. She nurses them all day but she still looks like her udder is full. I've never had a problem with her letting down but this year is different. I know she has milk but she still hangs on to it. She has always had a sensitive udder. I tried to use a milking machine and her udder got very red. Is there anything that I can give her to get her to let down? I know that she still is full.