We had a very hard winter in Texas. My Sago is mushy in the center of it as far down as I can reach; however, it has two babies coming out at the base. I removed all the dead fronds but don't know if it will revive or not? My Mexican Fan Palm, over 6 ft tall, turned all brown. When I peel back the top branches, I can see some green with black like charred on the ends. Will it come back, and what can I do to help these?
It does sound like the adult sago is dead, but you can replant the pups. The Mexican palm may still be alive and may come back if it is. This article will help you determine for sure:
https://www.gardeningknowhow.com/plant-problems/environmental/how-to-tell-if-a-plant-is-dead-and-how-to-recover-an-almost-dead-plant.htm
When is the best time to fertilize my shrubs/trees?
You can use chicken manure as long as it has been well rotted. This article will help with that:
https://www.gardeningknowhow.com/composting/manures/chicken-manure-fertilizer.htm
Spring is a great time to fertilize, as the plants will be heading into a growth period and then a few times through the summer and early fall. You want to back off of fertilizing in the winter (even in warmer areas) as the plant's growth slows some during this time.
Also I live in Phoenix, AZ.
These trees have a, somewhat, specific fertilization need. These articles will help:
https://www.gardeningknowhow.com/ornamental/trees/palms-trees/how-to-fertilize-palm-trees.htm
https://www.gardeningknowhow.com/houseplants/fan-palm/growing-mediterranean-fan-palms.htm
We have 2 Mexican palm trees in pots. I need to know how to water these plants so as not to over water and kill the trees. The pots are fairly large and I'm not concerned about repotting for another year or two. Just watering is my problem.
Since you have them in large pots, it's extra important not to overwater if there is a lot of excess soil. They need well draining soil and are slightly drought tolerant, so water when the soil begins to dry.
These articles should help:
https://www.gardeningknowhow.com/houseplants/fan-palm/growing-mexican-fan-palms.htm
https://plants.ces.ncsu.edu/plants/washingtonia-robusta/