Is okay to feed just feed and grass in the summers (horses out all the time) and feed and hay in the winters?

It depends on how much land your horse is on. One horse can completely graze down an acre inside of a year. If you do not want over grazed pastures, offer hay as well. My horse is on 1/4 of an acre and it has great grass. l offer him free choice hay and he would usually eat a 50 pound bale in 3-4 days, even with grazing. In the winter he would eat a bale in 2-3 days. So, he did eat less when there was good grass to graze on.

It is not a good idea- u want to feed some hay in the summer as well because grass is rich- horses will eat hay in the summer in addition to the grass, just not as much. If it is cost u worry about, just get the lowest quality hay (in richness- not sure where u are, but timothy is one type- no alfalfa) u can find & feed them that.

Another pro is that it will save ur pastures & u will have more grass- a horse needs a lot of pasture to be able to sustain itself on it. We have 2 acres per horse of alfalfa/timothy fields, plus feed 2-3 flakes of low quality hay in the summer, & they still would eat the pastures down to the bare dirt. We now have rotational grazing to help save the pastures.

Honestly? If ur horses r on pasture & u have good grass, I'd skip the feed, they just do not need it. My mare is on 24/7 pasture. She gets only grass (plus lots of treats lol) in the warmer months & supplemental hay in the winter, plus she is on a regular deworming schedule. l am sure l will get some thumbs down but my mare is 23 years old, festively plump, very sassy, & shines like a new copper penny. :)

Edit: Forgot to say, we have three horses on 10 acres of land. They r right, u do need several acres of pasture land per horse.

l agree with the poster above me. My horses have always been on 24/7 pasture board and never get hay in the summer. l take that back, they did get a small amount last summer b/c the drought was so bad and there was no grass in their pasture. Under normal circumstances, though, grass (as long as they are on enough pasture) and some feed is plenty.

My horses are on grass only in the summer. No grain and no hay.
Sometimes l give them a supplement but that is it.
They do not get hay until October and thru til May.

supplements:
Triple Crown 12% supplement (not grain)
or
Omegatin
or
Horseshoer is Secret
or
Vita Plus

If you can rotate your horses on your pasture and keep it healthy (pasture) you should not need to feed hay. l rotate 5 horses on 7 acres and can go all summer and do not need to feed hay until we get snow

It depends on how much grass their is on the land if little then give some hay. l have my horse on about 1 ac. with very very good grass l put more then 10 hours and 250 lb of nitrogen.if u put some fertilizer put some nitrogen with some Bermuda seeds (if u live in the south) or what ever grass you have in your area. .

It can be done if you have enough grass and if it is high enough quality.

l do not think that will be a good idea. Unlike wild horses, domesticated horses do not have thousands of acres of grass to graze on. Since they live in an enclosed area, they will cover the same ground twice before grass has the chance to grow back up.

Horses can eat up to 2 to 2.5% of their weight, so a 1,000 pound horse needs 20 to 25 pounds of forage a day. Depending on the size of the pasture, they will most likely mow it all down quickly if no hay is provided. If the pasture is medium or small sized, keep them on a dry lot (or in the stall if u do not have a dry lot) for part of the time so that this will not happen, & provide about 1 or 2 flakes of hay twice a day.

As for winter, since the grass will be harder to grow, do not put them out as much or keep them on the dry lot for most of their pasture time. Of course, as u said, extra hay will be needed then, & l could not tell u exactly how much since l do not know much about ur horses or the pasture, so l would recommend about 1-2 flakes four times a day, or 3-4 (maybe even 5, depending on ur situation) twice a day.

For more detailed information, l have found a site that has some calculations u can use to determine exactly what each horse needs.
http://extension.umn.edu/distribution/livestocksystems/components/0480_05.html

Good luck!!

perfectly fine- that what l do and several people around me with no negative effects.

If there is sufficient grass, then that is definately fine. Lots of people do that.

My horses are grass only during the summer ( with a tiny feed of mostly chopped carrots to get supplements into them) They do not get any hay until around November then they get it through to around Easter.
l have 7 acres and rotate around fields - if you have small acreage then you will need to feed hay year round.

It is fine, as long as u r not destroying ur pastures by overgrazing them. Horses r vigorous grazers & can do damage to the grasses that wo not recover if they graze too long in too small of an area. but as for nutrition, they do fine on grass with supplemental feed to balance any nutritional deficits in the grass. Some horses need nothing but pasture & a salt block & mineral block, & ample water. Others need additional calorie sources to keep weight on. It is best to have ur grasses & soil analyzed to recognize any deficiencies. l had a horse years ago that developed hypothyroidism from the lack of iodine in the pasture grasses. Once l supplemented her feed the thyroid function resumed normal. The average, healthy horse should do fine with it.