The swollen vent looks good, just a little pooched out, probably from constipation or pasty butt. Are you using a thermometer to watch the temperature in your brooder? What is it in the warmest spot. Since pasty butt is caused by shipping stress usually, make sure that your temperature is around 90 for the first week with a cooler spot to get to, and decrease it by 5 degrees each week by raising your lamp. Drinking plenty of water may ease her constipation.