PS is Performance Stats, the total of your horse's stats which you can view by clicking the 3rd tab on their page (the one with a little graph icon). you can gain more stats by training horses weekly, more ps means the horse can compete in higher discipline shows with bigger payouts. the wiki has a table where you can see all the showing tiers but since it's still down nobody can view it.

So are these foals good?

none of the links are working for me, they just take me to the hofa home page 

https://horsefable.com/horse/1795484

https://horsefable.com/horse/1795483

updated links

The higher the PS the better, those foals have very good PS.

Those foals are at an okay starting point. PS doesn't mean much at this stage though. TB, or Training Boost, is the number that really matters, because that determines how much PS a horse can gain over the course of its life as you train it. From the looks they haven't finished foal training yet, but it seems they'll have 9 or 10 TB once they have. 10 is about the minimum TB people look for when they're looking to buy a horse from someone. Personally I don't bother with anything less that 15 TB in most of my breeds now. I prefer to have 19 TB or 20. 

You can get foals with a higher TB by breeding higher level horses. TB = Mare's level + Stallion's level divided by 10. So if you breed a level 50 mare and a level 50 stallion, the foal will have 10 TB after foal training. Most people wait until horses are level 50 to breed them, but I wait until they are 17 or 18 years old, so they have the highest level possible (usually between level 70 and level 100 at this point, depending what working path I have them on.)

Here's a decent example of one of my foals https://horsefable.com/horse/1779328

I don't care much about the 2000PS (though it is nice), the 19TB however means it will gain +19PS every time it trains, on top of what it would get without the training boost. so that's 5x19 PS it will gain each week MINIMUM. It will quickly overtake a foal with a higher PS & only 10TB.