How are they doing now?
Do you have photos?
You put fresh bedding over the old - was the old bedding wet or moldy?
Mucous from the nostrils can be an indication of respiratory illness, but check you brooder and ventilation first. If the symptoms worsen or they become lethargic, seeking vet care if always best.
If that is not possible, they you may need to treat with antibiotics - Tylan50 can be found at most feed stores like Tractor Supply.
http://edis.ifas.ufl.edu/ps044
