Rock doves, the pigeon pests of the present, were once likable livestock. They could be eaten, their eggs could be eaten, and their poop was well regarded as fertilizer. If the farmers had known chemistry, they would have noticed that, like chicken manure, pigeon poop was high in nitrogen. but they did notice it made the plants grow greener and faster. This was all farm economy, but there were also pigeon breeders, pigeon fanciers, and people who sent messages with them, or raced them.

Dovecotes to attract and house pigeons were a feature of many estates in the pre-modern world, so likely the architects or builders would look at the job of designing and building one as just another job. Some dovecotes surviving from the time are quite well made,, so obviously pigeons were a valuable commodity and the builders presumably were therefore well-paid.

If the job of collecting the droppings was unpleasant, there would be plenty of that kind of job already: a farm laborer would be cleaning out stables, mucking out a barn, wading around in the muddy pigsty herding the pigs, and likely hauling off the "night soil" that had collected in an outhouse. And of course Charles Goodyear didn't get his patent for vulcanizing rubber until 1844, so no rubber boots for the farmhand to wear , either, so they generally would make do with wooden clogs and not risk their good shoes. If they had good shoes.

The feeding of the pigeons was done by the surrounding countryside. Which meant that birds could graze on other people's farms, other peoples' grain. This resulted in lawsuits and rules. The problem could have been big: in 1655 it's been estimated there were three substantial dovecotes in each parish of Britain. At eight thousand parishes, twenty four dovecotes, and each holding perhaps an average five hundred pigeons, that's twelve million birds.

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Michael Olmert Kitchens, Smokehouses and Privies: Outbuildings and the Architecture of Daily Life in the Mid-Atlantic