She has dropped a little but before I go into anything about feed/worming there are a couple of other things to consider:
1.) She has moved recently. TB’s do experience stress as a result of moving and stress can lead to poor digestion.
2.) Did she come from the track directly? If so, she was probably on rocket fuel food and as such her current feed is probably of a lower caloric value.
3.) It is heading into winter and TB’s can struggle in the colder weather, some do some don’t. Your girl might be one that does.
4.) Any combination of the above either acting alone or in concert.
I don’t know what your scoop measurement is but as a comparison, I feed my girl 2 ˝ scoops of pelleted feed a day which is equivalent to around 13 pounds daily. Plus free choice hay. She is worked 3 days a week and not overly hard – between 30 mins and 60 mins, mostly walk/trot work with some cantering.
Also, even though your girl may have lost some weight, it is minimal and you are getting onto it at the right time! I think you may just need to increase her feed. She is new to you, it will take some time to ‘get it right’ in terms of diet.
Before anyone mentions it, I don’t think it is a dental issue as they don’t usually present as an acute weight loss. However, you may want to consider having her teeth done as they may not have been done since she had her wolf teeth removed. Having them done may help with her digestion and continued weight gain.
I love her winter fuzzies!!
All horses deserve, at least once in their lives, to be loved by a little girl.