In the novel The Bronze Bow, was Amalek, the owner of Daniel, mean to him?

Yes. Daniel specifically runs away from Amalek to join Rosh's band in the mountains because of Amalek's harsh treatment. Daniel risked his life and nearly died running away from Amalek, which gives the reader an insight into how badly Amalek treated Daniel. In Chapter 1, Daniel introduces himself to Joel and Malthace, who are hiking up the mountain during their holiday break. Initially, Joel does not recognize Daniel. After Daniel tells Joel his full name, Joel remembers who he is and says,

"The apprentice who ran away from the blacksmith?...No one blamed you...Everyone knows how Amalek treats his boys" (Speare 4).

Daniel then tells Joel to give a message to Simon, another boy who worked under Amalek, explaining that he joined Rosh's band in the mountains. When Joel and Malthace leave, Daniel wishes that he could go back to the village but fears being enslaved to Amalek again. In the next chapter, Simon visits Daniel and tells him that he can come back to the village because Amalek is dead. Daniel is relieved to find out that his bond has expired because Amalek died without a relative to his name.