Try feeding her in there with the door open a couple of times, and then start to close the door. Spend the time not in the run with her but pottering about the garden and give her something to chew on or play with. Make sure she has had a good play before putting her in there, so she is tired and will probably lay and chew her bone or pigs ear, and then drop off to sleep. Ignore here is she whinges or whines and only do it for a short while at first, gradually increasing the time. Maybe go and make a cuppa and sit out in the garden not actually looking at her but watching out of the corner of your eye to see what she's up to. Shouldn't be a problem provided you don't keep pandering to her if she tries to get your attention. Another point, don't make too bit a thing of it when you take her out of there, so she won't feel she has been 'rescued', its just a matter of course.