Should we ask the seller for the fence to be repaired if the inspector did not include the broken fence slats in his report?
Yes, you can ask the seller to fix the fence slats even if the inspector did not include it in his report. While I do send the report to the seller with the repair amendment for the sellers review, I will note that you asked for the fence repair as well. The seller did not note any damage to the fence in the sellers disclosure. If this happened while the home is on the market, then I see no problem in asking the seller to repair even if it is not on the inspection report.