There is no one right answer for all horses regarding if certain grains are bad for them or not. Barley is considered to be fairly easily digested and provide a less sugary source of nutrition for horses than say, oats. However horses with certain metabolic issues should avoid starchy grains altogether. But if the horse has no issues and is in hard to heavy work then barley likely won't cause any problems if fed appropriately.
Yes its like eating grass from the ground.
if you want your horse to get sick in other words no no no!
Yes, they are fine for horses to eat, though some horses might not like them.
Not by the bucketload, but a few every now and then will be OK.
This depends on what you mean by 'stickers'. If you mean the soft sticky seeds that cling to your legs after walking through tall grass or the soft ball like seeds with tiny spines found in certain species of grass they are OK and horses eat them all the time. If you are referring to what are often called ' Sand spurs or sand stickers' then absolutely not. These hard brown seeds can and will get stuck to the horses mouth, tongue, gums and esophagus and cause pain which will require a equine veterinarian to come out and remove them.
No, not at all. Sickness and death of horses has occured when horses have eaten hay that has later found to have contained foxglove.
It's ok for horses to eat some Daisy's but too much of anything can be bad so just be sure they don't eat too much.
Cats do not generally eat grass, so there is no right or wrong answer to your question. If there is an individual cat eating grass, your best bet would be to observe it to find out how much grass it eats.
As long as no chemicals have been put on the grass :) they absolutely love it!
they moe the grass with there teeth! dah ok whoever is sad enough to look up this answer (you people need to get out more)
Horses with a light to medium workload will be fine on (and are actually better off with) only a grass/grass hay diet with a mineral block and fresh water. Make sure it is good quality grass hay. Do not feed much, if any, alfalfa; it is really rich and grass hay would be better. A few treats are ok too. Apples, carrots, sugar cubes, horse treats, are all fine in moderation. Grain is a common food for horses, but is not really necessary unless the horse is in a heavy workload and can do more harm than good for horses on a light to medium workload. you do not have to feed your horse only hay you could feed your horse speedybeat mix and you could also feed them a kind of barley and mints.
Clover is OK but not really very good for horses as it contains a fungus that can cause drooling and some other problems.