I have four hens that are now 2 years old. they have laid nicely for a 18 months. but they never molted last fall, still haven't, and are beginning to look a little frayed featherwise and eggshell wise too. I suspect they need a break...
you cannot tell the age by the comb. the comb is an indicator of health and egg production. your hens look healthy and young. I have no trouble believing they are the age said, but couldn't really say.
should help with your temp. they are made to get damp, besides it is under the water proof pool. this along with a heat lamp they can get under should suffice.