As demonstrated in Shirpour 2003 "The influence of hypothermia on thyroid function in rats" the level of T3 is ~110 ng/dL; T4 is 4.9 ng/dL and TSH is 0.037 uIU/mL
I got from a research by de Sibio et.al in 2013, they measured normal wistar rat fT3, fT4, and TSH and the result was fT3 (0.15 +/- 0.09 pmol/L), fT4 (46.2 +/- 1.6 pmol/L), TSH (14.2 +/- 0.9)