Animals

Hens
Hens are a reliable source for food and income. You are able to buy them at the beginning of the game, but it is recommended to repair the hen house first before you buy any hens.

The hens can be bought at the agricultural store for 25 euro per hen. You also get 100 kg chicken food when you buy a hen. Your hen house has place for 20 hens.

Once you have acquired the maximum of 20 hens, they will produce 40-60 eggs per day, every morning at 6:00am.

Rooster
Unlike hens, only one rooster can be bought at the agricultural store for €95.

The rooster lives in the hen house, and on sunny days can be seen perched up on the corner of the hen house fence.

With a rooster present, there is a small chance that an egg your hens have laid will hatch into a new hen. If this happens when you already have the maximum number of hens, a notification will appear that the new hen has been sold for €60-70.

Cows
Cows are a good source for milk... and manure (for fertilizing)! That's why they are very important to create a good farm.

The appropriate source of food for cows are straw bales. Every bale adds 200 kg of food to the storage in the cow barn. Cow food can also be purchased at the Agricultural Store.

Every cow gives about 2 to 3 milk every day, if they have enough food and the cow barn is fully repaired. The cow barn has place for 9 cows (which then produces 18-27 jugs of milk a day).

Cows can be bought at the agricultural store for 470 euro each.

Cows produce 1080 manure everyday. (Needs confirmation whether hens, ducks and geese also contributes, pigeons do not.)

Dog
Across the road from the store near your farm, a dog named Rex can be initially found.

In order to befriend Rex and have him live on your farm, he must be fed sausages four times. Sausages can be bought at the store or from some NPCs.

Rex can only be fed once per day, and once fed will travel to another location, requiring you to find him again. Since trying to find a tiny dog somewhere on this giant map is ridiculous, it is recommended you follow him until he stops, mark that location, and visit him there tomorrow with another sausage. Note that the closer you follow him, the slower he walks; you might want to back off enough that he's running. On the other hand, it's easy to lose sight of him if he goes through a sunflower field, so don't let him get too far ahead.

Or you can use this guide to find him, he should show up in the same places in every playthrough:

Location 2:  in the garden at the foot of the white house, at the farm just WSW of yours, north side of the road.

Location 3: In front of the metal gates of Oliver's homestead (remember repairing his barn in return for a tractor?) which is almost due south of the previous location, on the other side of the wheat field,

Location 4:  Outside the front gate of the Agriculture Store.

Once Rex is your permanent farm dog, the game will tell you to occasionally feed him another sausage to keep him loyal. However, he also seems to stay happy if you just pet him once in a while.

Cat
You may regularly see a notification that mice are eating the food stored in your pantry. Buying a cat from the agricultural store for €140 will prevent this loss of food.

The grey cat, named James, will then be seen resting in a number of places near the middle of your buildings. (Use Engineer Sight to help find him quickly).

Occasionally, you will have to feed him a fish to... keep him hungry enough to eat mice. (No, that doesn't make any sense; just go with it!)

Ducks and Geese
Ducks can be bought at the agricultural store for 33 euro each, while Geese cost 47 euro each.

You may purchase a maximum of 10 of each and they will nest in the straw barn next to each other, visiting the pond during the day.

Both will occasionally lay an egg (MUCH less often than hens) in the straw where they gather in the hay barn (one per animal). The eggs can be eaten raw. Duck eggs gives 15 nutrition while Geese eggs gives 20 nutrition. It does not seem to be usable in any recipes even though the game says it can, "Food. Can be eaten raw or used to prepare delicious dishes." Maybe the wife knows how to cook this (needs confirmation).

After collecting all the eggs you'll still see 20 uncollected eggs in Farm Statistic regardless whether you own any pigeons or not, it may be a bug that's related to Ducks and Geese since you can have 20 total and they all lay one egg each.

Pigeons
Pigeons can be bought at the agricultural store for 28 euro each.

Your Pigeon roost (a tall birdhouse next to the Gazebo) has a maximum of ten perches.

Pigeons do not appear to serve any purpose beyond decoration in the current game build.