A Prayer for Animals is a prayer which has been widely circulated and which is often attributed to Albert Schweitzer. However, it does not appear in his writings, and probably was not authored by Schweitzer.
There is a prayer for animals which Schweitzer composed and recited as a child. However it is quite short and is not the one widely known. Here it is, as translated by C. T. Campion, from Memoirs of Childhood and Youth:
O, heavenly Father, protect and bless all things that have breath;
guard them from all evil,
and let them sleep in peace.
Here is the more common Prayer for Animals, which is attributed to Schweitzer, although he was probably not the author. This version is from Animals, Nature and Albert Schweitzer
A Prayer for Animals
Hear our humble prayer, O God, for our friends the animals,
especially for animals who are suffering;
for animals that are overworked, underfed and cruelly treated;
for all wistful creatures in captivity that beat their wings against bars;
for any that are hunted or lost or deserted or frightened or hungry;
for all that must be put death.
We entreat for them all Thy mercy and pity,
and for those who deal with them we ask a heart of compassion
and gentle hands and kindly words.
Make us, ourselves, to be true friends to animals,
and so to share the blessings of the merciful.