I too am sorry that you have had health issues with your pekins. Are they jumbo pekins? My sons 3 and my one are not jumbo -- much smaller than my muscovy drakes. We have not had health issues except one eye infection with our pekins.
I agree with every point that BelovedBirds made above.
My son has pekins -- a drake and two females -- I have an all drake flock that includes 1 pekin and 3 muscovy.
Where are you and what is your soil like? Our ducks are in NE Florida on very sandy soil and we dont get mud. I am currently...