constipation in young beefers

I just got 3 limousin heifers ( my first) about 6 weeks ago. When they came they were all stressed, and I noticed they were all a bit constipated. Looked like deer turds not cow pats. I figured that when they got settled in and out on pasture, it would clear up. That has been a while now and they seem to be happy and eating well, but at least one is still passing stiff dry turds. Any ideas?

Saw a forum where they used mineral oil to loosen up the cow. Administer through tube down the nose or poured in waterer.