If she is all belly and no shoulders or butt, I would up her feed and protein. EVERYONE feeds different. We live in different areas, we have different beliefs, doesn't mean one is right or one is wrong....whatever keeps the horses in good shape.
An example of what my weanling are eating right now:
We live in northern California, and grow our own grass hay.
29" 8 mos. old filly, medium build. Should mature around 32
30" 10 mos. colt,(soon to be gelded) med. build. mature around 33"?
Both are in excellent weight, no bellies, chubby all around. Just like I like them going into winter.
AM: 2 cups Equine Jr
3 cups Omolene 200
then out to Irrigated green pasture.
PM: 3 cups Equine Jr.
3 cups Omolene 200
2 cups Alfalfa pellets
grass hay that is mostly Orchard grass.
On the days they don't go out because of weather, I will substitute soaked alfalfa cubes for the pellets just to make sure they get enough water into them.
I am not a fan of Equine Jr, but am trying it this year. The filly doesn't really care for it, so I will be giving her more Alfalfa pellets and dropping the Jr. They were getting omolene 300, but I just switched to 200. They get the alfalfa pellets because MYO , I think they need alfalfa. For ME, I think it goes back to the days of big horses, when our horses got Alfalfa and Oats...that was it...oh and that yellow vitamin..........clovite, thats it. And they looked awesome!!!!!
Oh, and I don't work my weaners other than to halter them, teach them to tie, clip, etc. The usual stuff.
They eat well. so they feel well and run and play a lot.
Hope this helps.
Sue