I agree with Marcial on that.
Although chondros can handle lower temperatures than many people think, the temperatures you have listed were too low to keep them at for a long period, in my opinion. Were you giving them their normal daytime basking areas during this period or keeping at the 55-65 constantly?
My pair was "cooled" down into the low 70s at night this past fall and winter, that was plenty to get them stimulated and get my girl gravid(she's entering her prelay shed now). Some nights my house got cooler and hit the high 60s, but these nights were few and far between, so didn't cause any damage. But dropping them constantly into the 55-65 range could possibly cause a whole range of problems, URI being a big one.
Either way, I hope your pair is doing alright now and I hope the copulations were successful. But keep the pair together until the male loses interest and the female stops eating. As I've learned that is probably your best indicator that mating has been successful.
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