Possible glitch/error??

[Stormchase Stables]

The pastures' grass is supposed to regenerate, right? Well, I have taken many turns but it seems to be going DOWN.
For example:
THIS MORNING:
Thoroughbred Youngsters pasture's grass is at 60%.
NOW:
The very same pasture's grass quality is at 54% - and I have definitely not mowed it. I took 12 turns since 9AM, and the quality is much lower than before.

Not a huge problem but just a kind of annoying glitch.

[Alaina]

When the pasture is stocked with horses they can eat the grass faster than it grows which causes the amount of grass to go down rather than up.

[Stormchase Stables]

When the pasture is stocked with horses they can eat the grass faster than it grows which causes the amount of grass to go down rather than up.

At the time that the quality of grass went down, there was only one horse in it and besides my other pastures with way more horses don't have that kind of thing happening. For example, my fullest pasture's grass quality always goes up, not down.

[Alaina]

When the pasture is stocked with horses they can eat the grass faster than it grows which causes the amount of grass to go down rather than up.

At the time that the quality of grass went down, there was only one horse in it and besides my other pastures with way more horses don't have that kind of thing happening. For example, my fullest pasture's grass quality always goes up, not down.

There's numerous factors that will affect grass quality. Grass won't grow as quickly, if at all, in winter so pay attention to the seasons. Young horses need to eat more to accommodate growth and larger horses will eat much more than smaller ones. Looking at your farm it looks like the grass quality of that particular pasture is now above 54% so it must be going up again.