Hello!
I've had seramas for four years now. I kept them inside for a year until my sister would not tolerate the dander anymore. So for the additional three years that some of my sweethearts lived, they lived in a custom-built house-- they had a heat source for a year and then the pen was moved and so not near enough an outlet to be turned on. I didn't think it made much of a difference anyway, as these guys were always exceptionally hardy and always ventured outside of the heated house on cold winter days.
Until last winter, their fifth year. I had two of my yellow-coloured chickens, my rooster and one of his hens, die of heart problems within a month of one another in spring (March and April). I believe this may have been the result of the lack of heat that winter, because my rooster's comb would be slightly purple-coloured at times during the winter. It must have been too hard on them. Loved these guys dearly and it sucks to think I may had accidentally contributed their death.
On the other hand, this may not have been directly caused by lack of heat and been heart failure present in the breed or in the genetics of these guys. And they were five years old-- not old, but heart problems may be more common at this age. Also, it's curious to note that the two who were yellow based died and the two that were black based, even though one, an 11 ounce gal, is alive and well. This does suggest to me something genetic, as well, that perhaps all seramas do not suffer from.
Anyway, when I was researching the breed I was always perplexed by the fact that there was this vague warning to give them heat with no stated consequences.
That's just stupid. It sounds like an old wives' tale and I can't really blame people for not listening. After all, the original jungle fowl and Ameraucana parents were from India and South America, and some of the heartiest breeds have evolved from them with time and breeding. I think if we could come up with a list of real consequences that could arise from not keeping them a little warmer, people might listen and understand.