Q.Fresh Chicken Manure
Is there a health issue if you allow your chickens to use the garden as part of the pen until it’s time to plant your seeds?

Certified GKH Gardening Expert
There is no real health issue, but your seeds will not grow well. Raw chicken manure is extremely high in nitrogen and will burn the seedlings. You need to compost it before putting it somewhere you what to plant seeds. This article will help: https://www.gardeningknowhow.com/composting/manures/chicken-manure-fertilizer.htm