Zombie book, part 2: how long wo..

Brief：
Okay, you may have seen my first question, so heres part two.Im writing a book about a zombie infestation and the main people come across a farm and f.. 

Okay, you may have seen my first question, so heres part two.

Im writing a book about a zombie infestation and the main people come across a farm and find two huge Shire horses in the barn. They are severely under weight, but the people want to take the horses with them, once they gain enough pounds.

So, how long would it take for the horses to get back their old strength once theyve been allowed to graze in the field everyday and eat hay in the barn, whenever they want? Oh, and if youre wondering why they havent died of dehydration, there is a pump system in their stalls that lead to the well, and that the horses can activate it by pushing a peddle with their noses. Like those things that are sometimes used in pigpens

Oh, and I mean a good few hundred pounds underweight

Thanks

I'd say a couple of months on lush grass will take them from thin to healthy weight. Your watering system sounds credible, and Shires can be believable in any setting - my guess is you were going for mildly exotic. They are not that uncommon...and they are easily ridden. There is a lady near here that has one trained for parade riding, and this is in the middle of rural Missouri - if they are here, they could pop up in your story (believably!) I did not see Part I, so I hope that does not matter.

***I went back and read Q 1, and I think Shires are a good choice for your story! ask your vet. To get into riding condition a horse that underweight may take 6 - 12 weeks. i'd say 6 months or so. unless it was only grass they consumed. then it would be around a year. If it was only on pasture and hay, it would take quite a while, most likely somewhere around 4-6 months. If it was feed other food items that have a higher fat content probably only around 2-3 months. Sigh... we actually DO have automatic waterers in the horse world. And they're not like the ones in pigpens. They're also ludicrously expensive to install. For consistency, make sure the facility they're in reflects the cost.