This study aimed to evaluate the effects of ground or steam-flaked corn and zinc-enriched yeast addition to grower pellet feed on fattening performance, rumen papillae development, and some blood parameters in lambs. For this purpose, thirty-six Kivircik male lambs were selected and divided equally into six groups: basal diet containing pellet feed without different corn form and yeast (control), basal diet 80% + ground corn 20% (PGC), basal diet 80% + steam-flaked corn 20% (PFC), PGC + Zn-enriched yeast (PGCZnY), PFC + Zn-enriched yeast (PFCZnY), and control + Zn-enriched yeast (PZnY). They were fed for 56 days according to the diets mentioned above. At the conclusion of the evaluations in fattening performance, rumen papillae development, and some blood parameters, there were no significant differences in body weight gain, average daily gain, average daily feed intake, and feed efficiency among the experimental groups. In the PGCZnY group, rumen papillae length was found to be higher than the other experimental groups. At the end of the trial (day 0), leukocyte and lymphocyte counts decreased significantly only in the control group compared with the other groups in the present study. Serum blood urea nitrogen (BUN) values, analyzed at the beginning and at the end of the trial, increased significantly in all groups except in the PGCZnY group. Supplementation of Zinc-enriched yeast to ground corn can be used for increasing ruminal papilla length, however decreasing the serum BUN levels in lambs during the fattening period.