Transactional replication very slow with indexes on Subscriber table

I have setup Transactional Replication for one of our databases where one table with about 5mln records is replicated to a Subsriber database. With every replication about 500-600.000 changed records are send to the Subscriber.

Since one month I see very strange behaviour when I add about 10 indexes to the Subscriber table. As soon as I have added the indexes replication speed becomes extremely slow (almost 3 hours for 600k records). As soon as I remove the indexes the replication is again very fast, about 3 minutes for the same amount of records.

I've searched a lot on the internet to solve this issue but can't find any explaination for this strange behaviour after adding the indexes. As far as I know it doesn't have to be a problem to add indexes to a Subscriber table, and it hasn't been before on another replication configuration we use.

Some information from the Replication Log:

With indexes on the Subscriber table
--------------------------------------
Total Run Time (ms) : 9589938 Total Work Time : 9586782
Total Num Trans : 3 Num Trans/Sec : 0.00
Total Num Cmds : 616245 Num Cmds/Sec : 64.28
Total Idle Time : 0 

Writer Thread Stats
Total Number of Retries : 0 
Time Spent on Exec : 9580752 
Time Spent on Commits (ms): 2687 Commits/Sec : 0.00
Time to Apply Cmds (ms) : 9586782 Cmds/Sec : 64.28
Time Cmd Queue Empty (ms) : 5499 Empty Q Waits > 10ms: 172
Total Time Request Blk(ms): 5499 
P2P Work Time (ms) : 0 P2P Cmds Skipped : 0

Reader Thread Stats
Calls to Retrieve Cmds : 2 
Time to Retrieve Cmds (ms): 10378 Cmds/Sec : 59379.94
Time Cmd Queue Full (ms) : 9577919 Full Q Waits > 10ms : 6072

Without indexes on the Subscriber table
--------------------------------------
Total Run Time (ms) : 89282 Total Work Time : 88891
Total Num Trans : 3 Num Trans/Sec : 0.03
Total Num Cmds : 437324 Num Cmds/Sec : 4919.78
Total Idle Time : 0 

Writer Thread Stats
Total Number of Retries : 0 
Time Spent on Exec : 86298 
Time Spent on Commits (ms): 282 Commits/Sec : 0.03
Time to Apply Cmds (ms) : 88891 Cmds/Sec : 4919.78
Time Cmd Queue Empty (ms) : 1827 Empty Q Waits > 10ms: 113
Total Time Request Blk(ms): 1827 
P2P Work Time (ms) : 0 P2P Cmds Skipped : 0

Reader Thread Stats
Calls to Retrieve Cmds : 2 
Time to Retrieve Cmds (ms): 2812 Cmds/Sec : 155520.63
Time Cmd Queue Full (ms) : 86032 Full Q Waits > 10ms : 4026


Can someone please help me with this issue? Any ideas? 

Pim