(See update post below) No injuries, no trauma at this point. Runners moved into back garden and storm shelter / alternate house. Changed my day's plans. Something had tried digging around the outside of the day pen a couple of nights ago. I lowered the bottom hot wire, and reckoned it was a rodent looking for a winter nesting spot. This morning I saw that it had dug under the kiddie pool. Oh, joy. The day pen has 2"x3" coated wire sides and top, with 2' of 1" coated poultry fence along the lower part of the sides. Apparently it climbed up the poultry fence and hopped through the larger gaps. I emptied the pool, found only a tunnel underneath. Time to add hardware cloth to the sides and top of the day pen. But what shall I do to fortify the bottom of the pen? Due to its location, a deep trench around it was not an option. The base is coated chain link fence sandwiched between boards around the perimeter. But rats are small enough to get through that. Design flaw. I was most concerned with larger predators. Concrete is not an option. Trenches - not an option. Thinking . . . a wide hardware cloth skirt around the perimeter? How wide? These things, as most probably know, can tunnel quite a distance. What might I place over the chain link fence that would last a while? Coated hardware cloth? Off to finish the upgrade to the winter shelter so I can have them in there safely. I'd rather they feel a little stir crazy for a few days than be harmed. And they'll have time out in the back garden, which they love. Rats!