I was telling my last foster dog's adoption coordinator how many times the dog poops every day, because I keep track, of course, and comparing the number to my own dog's poop activity. We were cracking up as she said, what is it with the weird pooping over there?
My dog poops 2, maybe 3 times per day, and eats 4 times as much as my foster dog. Dogs are not horses, obviously, but when you are taking care of them, their poop, how much there is, what it looks like, how bad it smells, etc, is just as important as horse poop. Thank goodness dogs can throw up!

Horses cannot throw up, and therein lies the importance of constant observation. If there is no poop, over several hours, that is very bad. If the poop changes from whatever normal is, to extremely dry and hard, that is bad. If it changes to very wet and runny, potential dehydration ahead.

No need to freak out, just ask some questions, or think back, if there is no one to ask but yourself...was the grass dry and brown last week and now it's fluorescent green? Did the temperature change 30-40 degrees in the last 36 hours? Did you handgraze him at a show? Is he peeing? Does he get nervous coming in the barn?
Sometimes diahhrea is just the horse responding to being taken away from his friends. If he is getting an impaction(a form of colic), it could be a sign that there is a blockage and only some stuff is getting out the back end.
If poop is dry, hard, and comes out in little individual balls, your horse could be dehydrated, which could be the result of eating hay for 24 hours in the stall, instead of grass. Keeping track of the color, consistency and amount, over a week's time, to start, is a good idea for new horse owners, and a good reminder for those of us who take care of multiple horses on a regular basis.
One of the most common types of colic I have seen is gas colic. Here in Virginia, the temperature swings we experience, especially in the fall and spring, can really make horses uncomfortable. When the temperature drops, the digestion slows down, but there is still all that grass in there, going nowhere. In the cold, horses may not drink as much, then gas pockets form. Usually, a little exercise or a blanket, when appropriate, can get the digestion system back to normal.
Learn how to listen for gut sounds and know what they mean, with or without a stethoscope.
Knowing your horse, in every way, is the most important. Where does he hang out in the field? How much water does he normally drink? Does he gobble grass or pick at it? When, where and for how long does he lie down? How does he show discomfort? Tail wringing? Pawing? Looking at his sides? Becoming depressed? Groaning? Lying down by the gate? Not lying down? Noticing discomfort and doing something about it can save your horse and save you a lot of money.
Each dog I foster(I just adopted out #29) is different, and while somehow dog poop will always be more gross to me than horse manure, at least dogs can solve digestive issues on their own, most of the time, by throwing up. Also gross, but, phew!

If I had to pick only 3 tools to groom a really dirty horse, a good challenge I hope I never have to deal with, and I couldn't use my horse vac(best client gift ever!), I would pick:
1. Hoof Pick...the first and most important tool, according to the US Pony Club manual, natch. I like the cheap steel ones with sort of a long neck and a thin, flat tip, like a screwdriver. No brush, no plastic, just pure leverage. It's good for scraping mud off of the outside of hooves, too!
2. Cactus cloth...it's weird, it is very old-fashioned, never needs to be cleaned, and it is amazing. It's like a 14"x20" piece bright straw-colored open-weave burlap that comes rolled up. You just wad it up and rub it on your horse, anywhere there is dried mud or sweat, and it disappears!  Use it all over-face, ears, belly, legs. It breaks up dirt without grinding it into the coat, and sensitive or clipped horses won't complain! Shake it out, throw it back on the shelf. Horses love to itch their heads on it. It is so gentle, especially when old and floppy, that my horse that gives himself mud eyebrows will let me rub it right over his eyes and under his lower lid.  Old school and I love it!
3. Leather-back body brush. The big kind with dense black bristles that aren't too soft, and about 1.5 inches long. The oval shape of the brush is perfect for every surface on the horse, and no wooden back to clunk into joints when brushing fast. Normally used along with a curry comb(to clean it as you go), this multi-tasker brings oils in the skin to the end of each hair for super shine, and will carefully detangle a tail or smooth a mane!
All those colored brushes and new-fangled tools at tack shops may seem appealing, but before hot running water and wash racks, horses still got shiny! I must admit, I would have a hard time without my horse vac, especially for a fuzzy beast after a muddy roll, but the simple tools are still the best.
What are your favorites?

Zulla Road, the big ex-timber horse I have in training, did his first Combined Test today, at a very low level, just to get him to a new place, and continue his transition from racing to a new life. He was very well-behaved, trotted the showjumping course with control, and had a great time, I think! 
Here is some of his commentary...:)

Look! A cute little jump! Whee! I think I cleared that by three feet!
Look, people! Oh!  Another jump! Yay! I only over jumped by 2 feet that time!  I'm trotting!  Fun!
Oo! A pond! Oh, that's outside the ring. Darn!  A green jump! I did it! More trotting!  Wow, this is fun!  Look, an orange jump!  Yay!  More jumps? Ok, fun! Let's do it!  Look at the geese!  Oo, another jump! This is easy!

Watching the best of the best compete, in any sport, is an education. Whether it is World Cup soccer, tennis at Wimbledon, Olympic swimming or 3-day eventing at Badminton, the sklls, technique and determination are worthy of observation and study.
It is not often that an upper level competition takes place down the road, even in Middleburg, where we have many top 3-day event and show-jumping riders based here.  This weekend, at Great Meadow, in The Plains, VA, the short list of US and Canadian riders selected to compete at the World Equestrian Games, in Normandy, France this September, will compete. I have my $50 parking pass, and my friends and I are going to go soak it all in and cheer them on!
There will be fit Thoroughbreds being finessed through difficult dressage tests, talented riders making the multiple element water complex look easy, and show jumping rounds under the lights on Saturday evening in the polo arena. I know I will learn something from watching these riders, I just don't know what it will be yet!
I am so thrilled that it is only 20 minutes away!

This spring and summer have been great for hacking in my neighborhood, just south of Middleburg, because, Spring lasted forever, so summer started late! We have had plenty of rain to keep things green, and although the ground is getting a bit hard, and the bugs can be brutal for Thoroughbreds, especially, we only get a couple super hot days per week. 
My friends have trailered in to ride out with me and my clients in small groups, weekly. The rides have been really good for foxhunters in training and green horses to settle in a small group(5-8), going slow. I have found that many small to medium-sized slow group rides, really takes the stress out of hacking for inexperienced horses AND riders. Then, when the opportunity for a hunt-sponsored ride comes up, hacking at the trot and getting left behind in a group of 40 is not such a big deal.