I would cut the heat completely... 14 chicks is enough to keep each other warm especially inside your house... even at day one during shipping according to most hatcheries.
Oh boy.. do I know about unexpected set backs!

Hope your hand is OK and recovers quickly and well.
Since everyone is acting normal... I probably wouldn't worry too much... unless you start to see bloody poos.
Bringing the plug of dirt in will give them a smaller amount of exposure to the stuff in your soil so they will be less likely to catch something when being put out full time.... Or short trips outside (to start) if you are able, are really good.
A giant (indoor) dog kennel... seems pretty crowded to me... but it's great that you aren't yet experiencing behavioral issues or coccidiosis. Don't get me wrong... I have over crowded sometimes! Oh the relief you will fill when you get them little buggers out... and how much fun to see them go spastic wing flapping and such with their new found space.