Reduce your readbatchsize, it's too high which is why you're seeing the message:

http://www.sqlservergeeks.com/blogs/Abhay_c/sql-server-bi/455/sql-server-fine-tuning-transactional-replication-performance-part-1

I've read that changing Readbatchthreshold can cause very slow performance in 2008

http://connect.microsoft.com/SQLServer/feedback/details/478792/using-the-readbatchthreshold-parameter-in-logreader-agent-leads-to-slow-performance