2 weeks ago I gave bird manure and my plant is sick now. how can I save could you help me?

It is really difficult to kill a dieffenbackia but I have managed to do it. I do not think it needed bird manure but that alone won't kill it unless... you added too much.

I suggest to remove all soil and re-pot it with fresh soil without bird manure. This plant does not need any bird manure.

I don't know the content of bird manure so I cannot be sure that it is the cause of the plant problems. If you suspect it is, then scrape off the manure if you added it on top. Otherwise, flush a lot of clear water through the rootball to wash the manure out. I don't recommend replacing the soil.

In general, it is best to limit non-sterile ingredients (manure, compost, garden soil, etc.) to outdoor use

I'm inclined to think that is a leaf spot disease, possibly bacterial (Xanthomonas) because there is a yellowish halo. Whether it could be related to the bird manure or is coincidental I don't know. I would follow Will's suggestions and monitor the spots to see if they get worse.