As long as the gaps aren't large enough to allow predators in (e.g., mice, weasels), you're better off leaving the gaps as they provide much-needed ventilation.Thanks. I went out and used some Great Stuff to seal up any gaps in the coop so it won't be as drafty. I've got a 250 watt heat lamp I was going to put out there for them, so I think that should be enough. Once I get the run built in the next couple of weeks, I will start letting them out in the day time when it's warm.