Q.Planting Japanese maples
I re potted a Japanese maple and added fertilizer
The fertilizer I added was chicken manure
It was 2 small shovel full. I am reading conflicting reports
Will this harm the plant
The pot is large 70 cm diameter

If the chicken manure was aged properly (composted) and if you mixed it in with the potting soil, then it won't hurt the tree. Problems could arise if the manure was not aged or if it was added in one layer just below the roots; this could cause the high nitrogen levels to burn the roots. Please see this article:
https://www.gardeningknowhow.com/composting/manures/chicken-manure-fertilizer.htm