my tb is 18 years old and is currently naked! she is in at night and out all day...I will start off with a cotton sheet and lightweight outdoor soon and then build her up (tho it has still been quite warm here).
It was only this weekend I noticed her coat had started to change and appear very slightly more dense...
I used to rug, rug, rug and more if I could but I am now not so inclined. My mare hates having rugs put on (fine having them off!) - she despices it most of the time no matter how you do it. Also, she is very fine skinned and whole winter of rugs on her can give her scurvy and her coat loses its gloss. So now I don't rug constantly and look at her coat changes to see what she needs.
The grass is growing like mad here and her full figure proves it, so she is showing no signs of weight loss!!