Michele, I meant to add that I am confused about why Odyssey is on Thyro-L if your concerned about weight loss? It is often prescribed for weight loss but hypothyroidism is extremely rare in equines and it's not recommended here or helpful. We recommend feeding either 1.5% of actual weight or 2% of ideal weight whichever is higher, it's just as important to not underfeed as it is to not overfeed. 

Bobbie and Desi (over the rainbow bridge 7/21) 
Utah, Nov 2018
NRC Plus 2020 , NAT , C&IR March 2021
ECIR Primary Response

https://ecir.groups.io/g/CaseHistory/files/Bobbie%20and%20Desi 

https://ecir.groups.io/g/CaseHistory/album?id=78821