I have recently came across a number of articles that have used Poisson GLMs when modelling proportion data. For instance, one study modelled the proportion of pig mortality for each sow using a Poisson GLM in SAS.
My experience with proportion data has been to model it using a beta regression or binomial-logistic regression (beta-binomial?), taking into account the bounds in the distribution. By contrast, my understanding of Poisson models is that they are only suitable for count, since the distribution is discrete.
Could someone explain to me whether a) this is common practice, and b) what are the implications of modelling proportion data using Poisson models?