As long as you're feeding grass hay, you can up their night time hay without hurting them. Depending how long they're shut in, I might up it by 1/3; if it doesn't get eaten, cut it back the next night.
Saturday was drizzly windy, cold and miserable. Sunday wasn't much better. Today the sun is out full but the wind's just about blowing everyone's tails around to their ears
I don't think we reached 50 today, so the wind chill's a zippy one.
Because of my two mid-20's Fellas, one has serious health issues, I wrestled each of these days with the blanket issue.
In the end, all four have been out every day with NO blankets. I said "guys, get out there and grow your winter hair. If you get cold, I'm watching and I will bring you in".
To add insult to injury, it frosted last night -- warm sun this AM, albeit very windy. I HAD to put the muzzle on my IR horse. Ask me how I liked that:(
Nobody stood with their head down and tail tucked, nobody came to the barn. But, make no mistake, as soon as it gets dark, they will be done being horses for this day and will want their jammies & clean shavings