"Ten pes vidí žrádlo."

[skywalker735]

And jídlo means?

[sanquii]

Jídlo is the regular way to say food. Žrádlo is very informal and may even be derogatory, which is why it's used for animal food here.

[endless_sleeper]

Žrádlo is not really derogatory or informal when used for animal food. Just don't use it for food intended for human consumption. The same applies for verbs: žrát vs jíst. It's similar to German fressen vs essen.