Of course we can put our plants out during the day and give them protection at night, or from freak bad weather that's not in keeping with our mental picture of continuous sunshine. Here, we call this gradual exposure to discomfort "hardening off". It toughens the cells of the plant which would otherwise be soft, lush and green from sugars and water. Being soft and sweet leaves plants vulnerable to weather, to aphid attacks, fungal diseases, what have you. A soft plant quickly becomes a dead plant. (Or, if you want to sound really fancy, you can say it's suffering from chronic necrosis.)
French beans, very much alive for now
It's not just plants that have to harden off around here. As long as it's dry, the Podgelets have been going outside in their puppy pen when the thermometer reads 10 degrees plus. The lambs stay out in the rain and cold now, with hedges and full bellies of milk to ward off chilling.
Tails ringed, ear tags in
The horses no longer get rugs put on them; they have to bear the transition into spring with a thin winter coat. Though they can put themselves in draught-free stables, they rarely do and accept the wind and rain on their backs as long as they can keep their heads down and eat the new shoots of spring grass.
Being cold causes warm fleece to grow, or increases appetite. Being wet ups the oil production to waterproof fur. It's all a trade-off: enduring some adversity to gain some strength. I think the same process happens with people, but on a psychological level instead of a physiological one. Heck, if the ability to grow hair was a strengthener against fear or anxiety, I would be an emotional Sampson (though I would resemble a Sasquatch).
Ram lamb's recovery more of a drama, as he had other bits ringed!
I hate inflicting any kind of stress or pain on my animals: docking tails, tagging ears, administering shots or horrible-tasting worming solutions. I try and keep in mind this concept of hardening off when a lamb struggles in my arms or a puppy shakes its head after a mouthful of worm paste. It's going to help you endure I remind them. And myself.
A pair of Podgelets do muscle resistance training with my riding boot