I got to pick out new chickens from the nice man down the road and when I got home I noticed that one of them has white goop on his/her rear??? Can someone help me identify this? The birds are about 16-18 weeks old, and this is the only one out of 20 that has it. She/he doesn't seem bothered by it and I haven't noticed any extra picking on him/her by the other birds when I watch them.
the only odd behavior I noticed is that he/she laid down on its side to take a poop the one time I saw it do so.
(edited to add pic)

the only odd behavior I noticed is that he/she laid down on its side to take a poop the one time I saw it do so.
(edited to add pic)
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