3rd cutting hay question

Hi,I have a question. Has anyone here had any problems with 3rd cutting hay and either impactions in their boars, or constipation? I started ordering 3rd cutting timothy in December, and one of our 7 boars developed motility issues right around Christmas. Another boar became badly impacted -- first time he has ever had this problem. I thought it was probably just a coincidence, until I switched back to Oxbow orchard grass two weeks ago. Now, feces are back to normal and (so far) no impaction. I love KMS hays, but wondered if this is just an isolated thing, or if others have noticed any digestive issues associated with 3rd cutting-? While researching this, I read an interesting article on HRS that talks about various hays and cuttings, and they do mention that 3rd cutting hay is too low in fiber for many rabbits. Are some pigs more sensitive to this than others?