Is it possible to share merit to all beings like Angels, hungry ghosts, animals etc I read stories in Petavatthu which describe how people offer donations to the sangha and transfer the merit to their deceased relatives who are born as hungry ghosts, so that they can get alleviate the suffering experienced by the hungry ghosts. In the same way, is it possible to share merit to other beings like Angels, animals, etc, because I haven't come across this in the texts.
Not sure Dhammadhatu's answer is direct answer for this question.
So sharing merit (telling your good merit) to animals doesn't work because they (almost every of animals) do not have any mind to understand good merit and eventually not able to be happy/together with you about your merit. So they will not share the effect of being happy/together of good merit.
Angles (frequently gods in Buddhist literature) may have little chance to know/care about your good merit since their lives are more about consuming the effects of good karma instead of cultivating good karma and sharing merit of others. There might possibility that some lower angels (gods) wandering on earth or living like human among us who can be shared our good merit but it is not so strong effects like on hungry ghosts because it is greatly differ in terms of necessity.